merge iOS arm64 lib to fat lib, change the project setting.
Merge branch 'v3' of https://github.com/cocos2d/cocos2d-x into merge_arm64_lib_to_fat_lib
fix lua compile error in xcode6 beta3
fix error.
Merge pull request #7449 from andyque/cleanupComments

update UI module code comments
[ci skip]
Merge pull request #7439 from boyu0/merge_arm64_lib_to_fat_lib

merge iOS arm64 libs to fat libs, change the project setting.