issue #1859:fix compiling error of AssetsManager.cpp
issue #1859:fix compiling error of ScriptingCore.cpp
Merge pull request #2574 from minggo/AssetsManager-asynchronization

Fix compiling error of AssetsManager project on windows
Merge branch 'master' of https://github.com/cocos2d/cocos2d-x into issue2092-XMLHttpRequest
Merge branch 'issue2092-XMLHttpRequest' of https://github.com/dumganhar/cocos2d-x into issue2092-XMLHttpRequest
issue #2092: Updating win32 project configuration.
issue #2092: Bug fix in MinXMLHTTPRequest::send
fixed #2092: Adding macro to make sure header file to be included only once.