Some modifications
- Moved the windows destruction from Common object to the Renderer.
- Shorted the DX11RenderSystem's members by size and changed the initialiyation order by the declaration order.
- Changed the DX11RenderSystem's functions declaration's order. Now the order of declaration and implementation is equal.
- Added a polimorf version for the Render::OnResize
- Corrected the ShutDown spelling case.