Merge pull request #1667 from pandamicro/develop-3.0

Feature #4010: Add retina enable function
Issue #4323： correct event manager jsDoc comments
Merge branch 'develop-3.0' of git://github.com/cocos2d/cocos2d-html5 into Iss4323_JsDoc
Merge pull request #1668 from dingpinglv/Iss4323_JsDoc

Issue #4323: correct event manager jsDoc comments
Issue #4323: Fix properties double declaration issue for jsDoc
Merge branch 'develop-3.0' of git://github.com/cocos2d/cocos2d-html5 into develop-3.0

Conflicts:
	tools/jsdoc_toolkit/build.xml
Issue #4323: Fix path issue in build.xml
Fixed #4227: correct a bug in CCTIFFReader.js for advanced compile.
Merge branch 'develop-3.0' of git://github.com/cocos2d/cocos2d-html5 into Iss4323_JsDoc
Merge pull request #1669 from dingpinglv/Iss4277_FixBugsForV3.0

Fixed #4227: correct a bug in CCTIFFReader.js for advanced compile.
Issue #4323: Fix singleton issue and function issue for jsDoc
Issue #4323: Fix duplicate issue for jsDoc
Merge branch 'develop-3.0' of git://github.com/cocos2d/cocos2d-html5 into develop-3.0