[GEARPUMP-237] remove manually downloading sbt launcher jar on travis

Author: manuzhang <owenzhang1990@gmail.com>

Closes #110 from manuzhang/fix_resolver.
diff --git a/.travis.yml b/.travis.yml
index 7151f88..e47393c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,10 +1,22 @@
 language:
 - java
 - scala
-sudo: false
-before_script:
-- mkdir -p $HOME/.sbt/launchers/0.13.13/
-- curl -L -o $HOME/.sbt/launchers/0.13.13/sbt-launch.jar http://dl.bintray.com/typesafe/ivy-releases/org.scala-sbt/sbt-launch/0.13.13/sbt-launch.jar
+sudo: required
+jdk:
+- oraclejdk8
+addons:
+  apt:
+    packages:
+      - oracle-java8-installer
+scala:
+- 2.11.8
+cache:
+  directories:
+  - $HOME/.m2/repository
+  - $HOME/.sbt
+  - $HOME/.ivy2
+git:
+  depth: 1
 script:
 - echo "TRAVIS_PULL_REQUEST" $TRAVIS_PULL_REQUEST
 - echo "TRAVIS_BRANCH" $TRAVIS_BRANCH
@@ -17,21 +29,7 @@
     then sbt -jvm-opts project/travis/jvmopts clean +assembly +publish | grep -v -E "$skipLogs"; sbt -jvm-opts project/travis/jvmopts scalastyle test:scalastyle it:scalastyle unidoc coverage  +test  | grep -v -E "$skipLogs";
   elif [[ $TRAVIS_TAG != "" ]];
     then sbt -jvm-opts project/travis/jvmopts clean +assembly +packArchiveZip | grep -v -E "$skipLogs";
-  fi  
-jdk:
-- oraclejdk8
-addons:
-  apt:
-    packages:
-      - oracle-java8-installer
-scala:
-- 2.11.8
-cache:
-  directories:
-  - $HOME/.m2
-  - $HOME/.ivy2
-git:
-  depth: 1
+  fi
 after_success:
 - if [[ $TRAVIS_PULL_REQUEST != "false" || $TRAVIS_REPO_SLUG != "apache/incubator-gearpump" || $TRAVIS_BRANCH == "master" ]];
     then bash <(curl -s https://codecov.io/bash);  
diff --git a/project/BuildGearpump.scala b/project/BuildGearpump.scala
index 1a52c40..8c9e438 100644
--- a/project/BuildGearpump.scala
+++ b/project/BuildGearpump.scala
@@ -41,10 +41,9 @@
   val commonSettings = Seq(jacoco.settings: _*) ++ sonatypeSettings ++
     Seq(
       resolvers ++= Seq(
+        // https://repo1.maven.org/maven2 has been added by default
         "apache-repo" at "https://repository.apache.org/content/repositories",
-        "maven1-repo" at "http://repo1.maven.org/maven2",
-        "maven2-repo" at "http://mvnrepository.com/artifact",
-        "sonatype" at "https://oss.sonatype.org/content/repositories/releases",
+        Resolver.sonatypeRepo("releases"),
         "clojars" at "http://clojars.org/repo"
       )
     ) ++
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 5f88b5e..0a6a562 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -16,8 +16,7 @@
  * limitations under the License.
  */
 
-resolvers += Resolver.url("fvunicorn",
-  url("http://dl.bintray.com/fvunicorn/sbt-plugins"))(Resolver.ivyStylePatterns)
+resolvers += Resolver.bintrayIvyRepo("fvunicorn", "sbt-plugins")
 
 resolvers += Classpaths.sbtPluginReleases