Fixed #4975: rename sp.Skeleton.createWithFile to sp.Skeleton.create
Merge branch 'v2.x' of https://github.com/cocos2d/cocos2d-html5 into Iss4975_Spine
Merge pull request #1833 from dingpinglv/Iss4975_Spine

Fixed #4975: rename sp.Skeleton.createWithFile to sp.Skeleton.create