Documentation fix: broken links and wrong encoding in the doc...

* Use C++ function names instead of Obj-C names when referencing functions.
* Changed some GB2312 encoded characters to UTF-8. （GB2312 encoded `’` is not valid UTF-8）
* Changed two `XXX class for cocos2d for iphone` description to `'XXX class for cocos2d-x'`.
* For `Object`, `AutoreleasePool`, and `PoolManager`:
    * Documentation added.
    * Applied the cocos2d-x C++ style guide.
    * Fixed some wrong indent.