fixed #1695 mutli scene resources loader
Merge branch 'iss1658_multiSceneLoading' of git://github.com/ShengxiangChen/cocos2d-js-tests

Conflicts:
	tests/tests_resources-html5.js
fixed multi scene resouces preloading bug.
It has been tested in Cocos2d-iPhone JSB.
Merge pull request #125 from linshun/master

fixed #1658: fixed some bug of multi resources preloading