[travis-ci] Speed up android build.
Merge pull request #2870 from dumganhar/master

[travis-ci] Speed up android build. [master]
Improving cocos2d-x cleanup on director end. Includes cleanup of ScriptEngine and CCApplication
Cleaning up ScriptingCore properly. Including deleting singleton and cleaning the registration list
 Fixed issues with sub animations not playing back correctly when animation in main template
Fixing bug in CCBReader regarding Scale9Sprites. Insets were not rendered correctly on iPad
Adding Android specefic tests for Killing and Switching activities
Adding DeviceSpecefic bindings for Android.
Adding support for dynamic custom TTF fonts in iOS.