set _node to null in createNodeWithSceneFile

_node was being set to null only in constructor, so when we call method createNodeWithSceneFile with path to existing file and then call it again with path to missing file (not calling destroyInstance method), it returns a pointer to previously created node, what may lead to a crash.
CCGLView: Add createWithFullscreen overloaded method that allows passing in Size, to set video mode.
CCGLView: Remove frameZoomFactor param from createWithFullScreen overload.
issue #4629: add test case for group command
issue #4629: test case add a spriteInGroup instead of sprite, the sprite can not be seen now
closed #4629: fix bug for group command
fix autotest touch hang:run test scene constructor in cocos thread
closed #4533:fix console upload hang issue
closed #4683: use assert because CCASSERT is not thread safe
Merge pull request #9 from pandamicro/develop

Sync Cocos2d-x
closed #4666, Update the build configuration files in template & update the reference of submodule cocos2d-console.
Merge branch 'develop' of https://github.com/cocos2d/cocos2d-x into issue4666
Merge pull request #6172 from natural-law/issue4666

Optimize the configuration of copy resources files in templates.
[Jenkins][ci skip]: Fix return value of git fail
closed #4629: remove unused _renderStack
Merge pull request #6171 from minggo/iss4683-assert_not_thread_safe

use assert because CCASSERT is not thread safe
Merge pull request #6173 from lmskater/fix-git-fail-return-value

[Jenkins][ci skip]: Modified the return value when git fails, it's used for `ci rebuild`
change QuadCommand::generateMaterialID() to private
Merge pull request #6174 from minggo/change-to-private

change QuadCommand::generateMaterialID() to private
Merge pull request #6168 from heliclei/fix-console-upload

closed #4533:fix console upload hang issue