Refactoring CCFileUtils. CrystalCraze works both on iOS and Android now.

* To test this Pull Request, you need to do as follows:

`git checkout -b new-branch`
`git pull https://github.com/dumganhar/cocos2d-x.git refactor-ccfileutils`
`git submodule update --init`.

**TO BE DONE:**
* Adding file cache support.
* Adding win32 support.
* Probably we need to add the default  strategy of resource structure rather than setting it at AppDelegate.cpp.