refactor touch event
remove UIInterface.h header file
restore Widget's constructor and destructor to public
restore UIScrollView constructor and destructor to public
Merge pull request #7006 from natural-law/v3

Update the reference of submodule plugin-x.
[AUTO][ci skip]: updating cocos2dx_files.json
Merge pull request #7007 from CocosRobot/update_cocosfiles_1402282382

[AUTO][ci skip]: updating cocos2dx_files.json
Merge pull request #7005 from andyque/refactorUITouchEvent

refactor UI framework touch handling