Merge pull request #1514 from pandamicro/develop

Fixed #3838: Allow retina display only on apple device to resolve the bug
Fixed #1516: _tileProperties should be a dictionary object
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss3825_SimpleAudioEngine
Merge pull request #1517 from dingpinglv/Iss1516_tileProperties

Fixed #1516: cc.TMXTileMap._tileProperties should be a dictionary object
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into develop