Merge pull request #2076 from pandamicro/develop

Fixed #5977: Add cc.sys.platform and improve inline document
Fixed #5781: fixed a bug of cc.Sprite that its setVisible is invalid when using BatchNode
Merge branch 'develop' of git://github.com/cocos2d/cocos2d-html5 into Iss5781_ReleaseV3rc2
Merge pull request #2078 from dingpinglv/Iss5781_ReleaseV3rc2

Fixed #5781: fixed a bug of cc.Sprite that its setVisible is invalid when using BatchNode
Fixed #5782: add a directory to .gitignore
Merge pull request #2079 from dingpinglv/Iss5781_ReleaseV3rc2

Fixed #5782: add a directory to .gitignore
Fixed a bug of spine that it doesn't work on WebGL
Update the CHANGELOG.txt
Merge pull request #2080 from dingpinglv/Iss5781_ReleaseV3rc2

Fixed a bug of spine that it doesn't work on WebGL
Fixed #599: fixed the bug that hexagonal tilemap on Canvas mode position is error
Merge pull request #2081 from dingpinglv/Iss599_HexagonalTilemap

Fixed #599: fixed the bug that hexagonal tilemap on Canvas mode position is error
[Doc] Add change logs and authors