Merge pull request #369 from yinjimmy/develop

update code from master branch
修复player下调用CCImage::saveToFile 导致断言崩溃问题, CCRenderTexture可以保存到文件
Merge pull request #370 from justbilt/develop

修复player下调用CCImage::saveToFile 导致断言崩溃问题, CCRenderTexture可以保存到文件
Merge pull request #389 from chukong/develop

Develop