Issue #2981: cc.EGLView supports "viewport" for multiple resolution on mobile.
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss2981_RefactorEGLView
Merge pull request #1192 from dingpinglv/Iss2981_RefactorEGLView

Issue #2981: cc.EGLView supports "viewport" for multiple resolution on mobile browser.