issue #5176, add UIFocusManager
issue #5176, add ListView focus test
issue #5176, fix override problems
issue #5176, remove unneeded functions in UIPageView
issue #5176, refacotr UIPageView
issue #5176. fix UIScrollView
issue #5176, refacotr UIPageView
issue #5176, refactor UIPageView
issue #5176, refactor UIPageView
issue #5176, refactor Layout and UIPageView
issue #5176, refactor AutoScrollDirection in UIPageView
issue #5176, rename UIScrollInterface to ScrollViewProtocol
issue #5176, refactor passTouchEventToParent method of UIWidget
issue #5176, readd addChild methods into UIListView
issue #5176, fix a typo
issue #5176, refactor UIScrollView
issue #5176, add focus to UIScrollView
issue #5176, add focus event listener to UIScrollView
Merge branch 'v3' into 5176

Conflicts:
	build/cocos2d_libs.xcodeproj/project.pbxproj
	cocos/ui/UIPageView.cpp
	cocos/ui/UIScrollView.cpp
	cocos/ui/UIScrollView.h
issue #5176, refactor UICheckBox releaseUpEvent