Merge pull request #1739 from pandamicro/develop-3.0

Fixed #4670: Add null callback check in cc.textureCache.addImage
Fixed #4675: Update default cocos2d-html5 path to frameworks
Merge branch 'develop-3.0' of git://github.com/cocos2d/cocos2d-html5 into develop-3.0
Clean up template