travis: test matrix build

.travis.yml

@@ -6,8 +6,14 @@ branches:
   - master
   - v3.1
 
-jdk:
-  - oraclejdk8
+matrix:
+  include:
+  - jdk: oraclejdk8
+    os: linux
+    env: UPLOAD_ALL=true
+  - jdk: openjdk7
+    os: linux
+  - os: osx
 
 before_cache:
   - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
@@ -18,6 +24,11 @@ cache:
     - $HOME/.gradle/caches/
     - $HOME/.gradle/wrapper/
 
+before_script:
+  - 'echo "Tag: $TRAVIS_TAG"'
+  - 'echo "OS: $TRAVIS_OS_NAME"'
+  - 'echo "PR: $TRAVIS_PULL_REQUEST"'
+
 notifications:
   slack:
     on_success: change