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
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