Update Cocos2d-x to release version
Add submodules verification to verify script
Updated growthpush-ios to v.1.1.2 and growthpush-android to v.1.1.1
Change Cocos2d-x version to 3.1-alpha2
Update README.md
Regenerate sample project
Add Growth Push code to sample
Add AlertActivity to AndroidManifest.xml
Update growthpush-ios submodule commit
Merge branch 'feature-update-cocos2dx'