Cocos2dx v32

Supports cocos2d-x v3.2

* Changes `draw()` with the new v3.2 API: `bool transformUpdated` -> `uint32_t transformFlags`
* cocos2d-ified the API:
    * `const char*` -> `const std::string&`
    * constructors and destructors are `protected` (not `public`)
    * using `_` prefix for ivars
Since cocos2d-x uses its own memory model with `retain(), release()`, and `autorelease()` it is better to create objects using the `create` static method instead of calling the constructor/destructors directly... just to prevent errors. I saw some memory leaks / crashes in users code because of that.

So, I moved the constructor/destructor to `proctected` to prevent that bug.