Update Pants to 1.6.0 and Virtualenv to 16.0.0

Beyond a regular version bump, this fixes the build on older versions of MacOS.

Testing Done:
./build-support/jenkins/build.sh

Reviewed at https://reviews.apache.org/r/67326/
diff --git a/build-support/jenkins/build.sh b/build-support/jenkins/build.sh
index a597539..81e60b8 100755
--- a/build-support/jenkins/build.sh
+++ b/build-support/jenkins/build.sh
@@ -25,9 +25,7 @@
 
 # Run remaining Python style checks and all tests
 ./build-support/python/checkstyle-check
-# AURORA-1972: As a workaround for spuriously failing tests, test different
-# targets in isolation
-./pants test.pytest --no-test-pytest-fast src/test/python:: -- -v
+./pants --cache-ignore test.pytest src/test/python:: -- -v
 
 # Ensure we can build python sdists (AURORA-1174)
 ./build-support/release/make-python-sdists
diff --git a/build-support/python/checkstyle-check b/build-support/python/checkstyle-check
index 7e65dd9..87daf40 100755
--- a/build-support/python/checkstyle-check
+++ b/build-support/python/checkstyle-check
@@ -18,6 +18,5 @@
 
 HERE=$(cd `dirname "${BASH_SOURCE[0]}"` && pwd)
 
-# TODO(John Sirois): Consider using `./pants changed` as a feed for this check.
-# We need not be checking the whole repo on evey commit.
-$HERE/../../pants lint.pythonstyle src/{main,test}/python::
+# Lint everything except targets with native Mesos deps that might be missing on dev machines
+$HERE/../../pants lint.pythonstyle src/{main,test}/python:: --tag=-mesos-native
diff --git a/build-support/thrift/thriftw b/build-support/thrift/thriftw
index 26b4f9c..bc9c0fb 100755
--- a/build-support/thrift/thriftw
+++ b/build-support/thrift/thriftw
@@ -91,7 +91,7 @@
 
 thrift="$(compatible_system_thrift)"
 if [[ -z "${thrift}" ]]; then
-  readonly pants_thrift_version="$(get_pants_option thrift-binary version)"
+  readonly pants_thrift_version="$(get_pants_option thrift version)"
   if [[ "${expected_version}" != "${pants_thrift_version}" ]]; then
     echo "Pants thrift version ${pants_thrift_version} does not match expected version ${expected_version}!"
     exit 1
diff --git a/build-support/virtualenv b/build-support/virtualenv
index d6484f5..a197f36 100755
--- a/build-support/virtualenv
+++ b/build-support/virtualenv
@@ -14,7 +14,7 @@
 #
 # Wrapper for self-bootstrapping virtualenv
 set -ex
-VIRTUALENV_VERSION=15.1.0
+VIRTUALENV_VERSION=16.0.0
 
 if which python2.7 >/dev/null; then
   PY=`which python2.7`
diff --git a/pants b/pants
index 312dd20..cdfe9b2 100755
--- a/pants
+++ b/pants
@@ -32,7 +32,7 @@
 PANTS_HOME="${PANTS_HOME:-${HOME}/.cache/pants/setup}"
 PANTS_BOOTSTRAP="${PANTS_HOME}/bootstrap-$(uname -s)-$(uname -m)"
 
-VENV_VERSION=15.0.2
+VENV_VERSION=16.0.0
 
 VENV_PACKAGE=virtualenv-${VENV_VERSION}
 VENV_TARBALL=${VENV_PACKAGE}.tar.gz
diff --git a/pants.ini b/pants.ini
index 8c71b14..41381ad 100644
--- a/pants.ini
+++ b/pants.ini
@@ -12,7 +12,7 @@
 # limitations under the License.
 
 [GLOBAL]
-pants_version: 1.4.0.dev23
+pants_version: 1.6.0
 
 plugins: [
     'pantsbuild.pants.contrib.python.checks==%(pants_version)s',
@@ -26,8 +26,11 @@
     'pants.backend.python',
   ]
 
+# allow imports in BUILD files to read .auroraversion
+build_file_imports: allow
 
-[thrift-binary]
+
+[thrift]
 version: 0.10.0
 
 
@@ -35,6 +38,12 @@
 interpreter_constraints: CPython>=2.7,<3
 
 
+[test.pytest]
+# AURORA-1972: As a workaround for spuriously failing tests, test different
+# targets in isolation
+fast: False
+
+
 # We have some modules that have side-effects upon import, including starting a repl, so we can't
 # use python-eval to validate our BUILD deps currently.
 [lint.python-eval]
diff --git a/rbt b/rbt
index 7531fcb..2a4549c 100755
--- a/rbt
+++ b/rbt
@@ -24,7 +24,7 @@
   rm -fr "$HERE/build-support/rbt.venv"
   "$HERE/build-support/virtualenv" "$HERE/build-support/rbt.venv"
   source "$HERE/build-support/rbt.venv/bin/activate"
-  python -m pip install --use-wheel "RBTools==$RBTOOLS_VERSION"
+  python -m pip install "RBTools==$RBTOOLS_VERSION"
   echo $RBTOOLS_VERSION > "$HERE/build-support/rbt.venv/BOOTSTRAPPED"
 fi
 source "$HERE/build-support/rbt.venv/bin/activate"
diff --git a/src/main/python/apache/aurora/executor/BUILD b/src/main/python/apache/aurora/executor/BUILD
index 486230d..f4e188f 100644
--- a/src/main/python/apache/aurora/executor/BUILD
+++ b/src/main/python/apache/aurora/executor/BUILD
@@ -55,7 +55,10 @@
     # TODO(ksweeney): This violates the rule that every library export the same deps as its
     # contained binaries.
     '3rdparty/python:mesos.executor',
-  ]
+  ],
+  # The binary can only build when the native Mesos dependency has been prefetched. This tag
+  # allows us to skip this target on development machines if necessary.
+  tags=['mesos-native']
 )
 
 python_library(