issue #5183, add CCLayoutExecutant file
issue #5183, refator LayoutExecutant
issue #5183, add LayoutProtocol
issue #5183, done
issue #5183, done
issue #5183, remove no needed type
Merge branch 'v3' into refactorLayout

Conflicts:
	cocos/ui/UILayout.cpp
issue #5183, add layout parameter type to widget for convenient access
Merge branch 'v3' into refactorLayout

Conflicts:
	build/cocos2d_libs.xcodeproj/project.pbxproj
Merge branch 'v3' into refactorLayout
issue #5138, add Groups in Xcode
issue #5183, refactor
issue #5183, refactor obscure functions
issue #5183, refactor UIScrollView
issue #5183, add deprecated function for Widget
Merge branch 'v3' into refactorLayout
issue #5183, refacotr some variable names
issue #5183, fix android compile error
issue #5183, fix win32 compile error
issue #5183, refactor