Issue #3221: set design resolution size a default value and re-implement _adjustSizeKeepCanvasSize function in EGLview
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss3221_ReleaseV2.2.1
Merge pull request #1240 from dingpinglv/Iss3221_ReleaseV2.2.1

Issue #3221: set design resolution size a default value and re-implement _adjustSizeKeepCanvasSize function in EGLview