ARIA-297 Make use of Apache RAT for compliance

Made use of Apache RAT for validating compliance; Created
a .rat-excludes file and added missing licenses where needed.

Additionally, added the DISCLAIMER file to MANIFEST.in.

Also, fixed a small issue in the "clean" target in Makefile.
diff --git a/.rat-excludes b/.rat-excludes
new file mode 100644
index 0000000..aa0e3b8
--- /dev/null
+++ b/.rat-excludes
@@ -0,0 +1,24 @@
+CONTRIBUTING
+DISCLAIMER
+VERSION
+NOTICE
+MANIFEST.in
+requirements.txt
+requirements.in
+docs
+dist
+build
+apache_ariatosca.egg-info
+.git
+.gitignore
+.gitattributes
+.coverage
+.coveragerc
+.rat-excludes
+.*.yaml
+.*.html
+.*.pyc
+.*.md
+.*.rst
+.*.iml
+.idea
diff --git a/MANIFEST.in b/MANIFEST.in
index 020b00e..6b67894 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,4 +1,5 @@
 include CONTRIBUTING
+include DISCLAIMER
 include LICENSE
 include NOTICE
 include VERSION
diff --git a/Makefile b/Makefile
index 50675bf..71a1968 100644
--- a/Makefile
+++ b/Makefile
@@ -27,10 +27,10 @@
 	@echo "Please choose one of the following targets: clean, install, install-virtual, docs, test, dist, requirements.txt"
 
 clean:
-	rm -rf "$(DIST)" "$(HTML)" .tox .coverage*
+	rm -rf "$(DIST)" "$(HTML)" build .tox .coverage*
 	-find . -maxdepth 1 -type f -name '.coverage' -delete
-	-find . -maxdepth 1 -type d -name '.coverage' -exec rm -rf {} \; 2>/dev/null
-	-find . -maxdepth 1 -type d -name 'build' -exec rm -rf {} \; 2>/dev/null
+	-find . -type f -name '*.pyc' -delete
+	-find . -type d -name '__pycache__' -prune -exec rm -rf {} \; 2>/dev/null
 
 install:
 	pip install .[ssh]
diff --git a/appveyor.yml b/appveyor.yml
index cb1ae42..a03b180 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,3 +1,18 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 environment:
 
   TOX_ENV: pywin
diff --git a/aria/orchestrator/execution_plugin/ssh/tunnel.py b/aria/orchestrator/execution_plugin/ssh/tunnel.py
index 6fc8d54..e76d525 100644
--- a/aria/orchestrator/execution_plugin/ssh/tunnel.py
+++ b/aria/orchestrator/execution_plugin/ssh/tunnel.py
@@ -1,3 +1,19 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
 # This implementation was copied from the Fabric project directly:
 # https://github.com/fabric/fabric/blob/master/fabric/context_managers.py#L486
 # The purpose was to remove the rtunnel creation printouts here:
diff --git a/examples/hello-world/scripts/configure.sh b/examples/hello-world/scripts/configure.sh
index b55ec17..9ac26d5 100755
--- a/examples/hello-world/scripts/configure.sh
+++ b/examples/hello-world/scripts/configure.sh
@@ -1,4 +1,18 @@
 #!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
 set -e
 
diff --git a/examples/hello-world/scripts/start.sh b/examples/hello-world/scripts/start.sh
index 96298c5..010af2c 100755
--- a/examples/hello-world/scripts/start.sh
+++ b/examples/hello-world/scripts/start.sh
@@ -1,4 +1,18 @@
 #!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
 set -e
 
diff --git a/examples/hello-world/scripts/stop.sh b/examples/hello-world/scripts/stop.sh
index 5461caf..e393dbf 100755
--- a/examples/hello-world/scripts/stop.sh
+++ b/examples/hello-world/scripts/stop.sh
@@ -1,4 +1,18 @@
 #!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
 set -e
 
diff --git a/tests/end2end/__init__.py b/tests/end2end/__init__.py
index e69de29..ae1e83e 100644
--- a/tests/end2end/__init__.py
+++ b/tests/end2end/__init__.py
@@ -0,0 +1,14 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
diff --git a/tests/orchestrator/workflows/executor/test_process_executor.py b/tests/orchestrator/workflows/executor/test_process_executor.py
index 6cac288..d3e7a6d 100644
--- a/tests/orchestrator/workflows/executor/test_process_executor.py
+++ b/tests/orchestrator/workflows/executor/test_process_executor.py
@@ -78,6 +78,7 @@
             executor.execute(MockContext(model, task_kwargs=dict(function='some.function')))
         assert 'closed' in exc_info.value.message
 
+    @pytest.mark.skipif(os.name == 'nt', reason='uses bash script')
     def test_process_termination(self, executor, model, fs_test_holder):
         argument = models.Argument.wrap('holder_path', fs_test_holder._path)
         model.argument.put(argument)
diff --git a/tests/resources/scripts/test_ssh.sh b/tests/resources/scripts/test_ssh.sh
index bbdf773..4261d7e 100644
--- a/tests/resources/scripts/test_ssh.sh
+++ b/tests/resources/scripts/test_ssh.sh
@@ -1,4 +1,19 @@
 #!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
 
 set -u
 set -e
diff --git a/tests/resources/service-templates/tosca-simple-1.0/node-cellar/workflows.py b/tests/resources/service-templates/tosca-simple-1.0/node-cellar/workflows.py
index 06e4f9e..fdca65d 100644
--- a/tests/resources/service-templates/tosca-simple-1.0/node-cellar/workflows.py
+++ b/tests/resources/service-templates/tosca-simple-1.0/node-cellar/workflows.py
@@ -1,3 +1,19 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
 from aria import workflow
 from aria.orchestrator.workflows.api import task
 from aria.orchestrator.workflows.exceptions import TaskException