Merge pull request #1039 from linshun/iss2580_v2.1.5

issue #2580: merged v2.1.5 to master branch
Merge pull request #1043 from linshun/iss2580_v2.1.5

Merged v2.1.5 to master branch
fixed #2468 Fixed a bug of CCBReader that ControlButton doesn't work when controller is _jsControlled
fixed a bug that engine can't load from single engine file
Merge pull request #1055 from dingpinglv/Iss_FixBuildxmlBug

fixed a bug that engine can't load from single engine file
Merge pull request #1054 from dingpinglv/Iss_FixBuildxmlBug

Fixed a bug that engine can't load from single engine file
fixed #2468 CCBReader has supported loading ControlEvents of ControlButton on _jsControlled Mode
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss2468_FixCCBReaderBug
 Fixed #2445 Fixed bug for sortAllChildren ,that tempChild is a changing var
Merge pull request #1057 from xingsenma/sortAllChildren

 Fixed #2445 Fixed bug for sortAllChildren ,that tempChild is a changing Var
 Fixed #2445 Fixed bug for sortAllChildren ,that tempChild is a changing Var.
Merge pull request #1058 from xingsenma/sortAllChildren

 Fixed #2445 Fixed bug for sortAllChildren ,that tempChild is a changing Var
fixed #1056 The bug of cc.ProgressTimer has fixed that Midpoint is wrong on Canvas Mode.
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss1056_FixProgressAnchorPointBug
Merge pull request #1059 from dingpinglv/Iss1056_FixProgressAnchorPointBug

fixed #1056 The bug of cc.ProgressTimer has fixed that Midpoint is wrong on Canvas Mode.
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-html5 into Iss2468_FixCCBReaderBug
fixed #2468 Corrected a mistake of cc.NodeLoader
Merge pull request #1053 from dingpinglv/Iss2468_FixCCBReaderBug

fixed #2468 Fixed a bug of CCBReader that ControlButton doesn't work when controller is _jsControlled
fixed #2497 : setSearchPaths Bug
Fixed #2481 Re-write Canvas Mode of RenderTexture to adapt WebGL interface