Merge pull request #96 from OneSignal/gradle_upgrade

Upgraded to gradle 2.14.1

Author: jkasten2

.travis.yml

@@ -12,9 +12,9 @@ android:
   licenses:
     - '.+'
 before_install:
-    - wget http://services.gradle.org/distributions/gradle-2.10-bin.zip
-    - unzip gradle-2.10-bin.zip
-    - export GRADLE_HOME=$PWD/gradle-2.10
+    - wget http://services.gradle.org/distributions/gradle-2.14.1-bin.zip
+    - unzip gradle-2.14.1-bin.zip
+    - export GRADLE_HOME=$PWD/gradle-2.14.1
     - export PATH=$GRADLE_HOME/bin:$PATH
     - cd OneSignalSDK/app
 script: gradle build