issue #4221 Refactor UILabel to UIText
issue #4221 Refactor constant for UILayout
issue #4221 Refactor constant for Layout
issue #4221 Refactor constant for ListView
issue #4221 Refactor constant for PageView
issue #4221 Refactor constant for ScrollView
Issue #4277: correct the mistake for renaming cc.AnimationCache
Feature #3942: Apply extension singleton objects in samples
Merge branch 'tests_js_3.0' of https://github.com/cocos2d/cocos2d-js-tests into tests_js_3.0

Conflicts:
	tests/CocoStudioTest/GUITest/UIScene.js
issue #4221 Refactor constant for gui
Merge branch 'tests_js_3.0' of https://github.com/cocos2d/cocos2d-js-tests into tests_js_3.0
Refactor #4240: Refactor purgeSharedAnimationCache function to _clear
Merge pull request #358 from pandamicro/tests_js_3.0

Feature #3942: Apply extension singleton objects in samples
Merge pull request #359 from xingsenma/tests_js_3.0

issue #4221 Refactor constant for gui
Issue #4277: update EditBoxTest.js
Merge branch 'tests_js_3.0' of https://github.com/cocos2d/cocos2d-js-tests into Iss4277_FixBugsForV3.0
Merge pull request #360 from dingpinglv/Iss4277_FixBugsForV3.0

Issue #4277: update EditBoxTest.js and correct the mistake for renaming cc.AnimationCache
issue #4221 rename gui namespace ccs to ccui
Merge pull request #361 from xingsenma/tests_js_3.0

issue #4221 rename gui namespace ccs to ccui
Merge branch 'tests_js_3.0' of https://github.com/cocos2d/cocos2d-js-tests into tests_js_3.0_ccgame