Rename all GetFOO and SetFOO to getFOO and setFOO
- rename Get to get
- rename Set to set
Refactory Scene
- Scene's MakeCurrent should be Bind() and UnBind(), that is more clear function name
- Scene should not have Init() and Destory(), but Load() and UnLoad()
    - Scene will new/delete the Renderables' memory
    - Renderer will call Renderables' Init() and Destory() in its own Init() and Destory()
    - Scene is a producer
    - Renderer is consumer
Refactor of Renderer
- Renderer have its own Bind with Scene
    - bind from Renderer to Scene is also good
    - now we have both bind from Scene to Renderer and Renderer to Scene
- Add some NULL Check for m_pRenderablesVector and its items when loop
Refactor to move Scene from AndroidApplication to AndroidTask
- remove Scene's new and delete from Application class
- add Scene to AndroidTask, that is good
    - it's easy to bind with message handle in AndroidTask
    - easy to switch different scene with different android message