Fixed rendering with OpenGL core profile

Added (automatic) support of Vertex Arrays Objects (VAO) to fix
rendering with an OpenGL core profile (OpenGL 3.2 require the use of
VAOs)
Added level check to NzImage::GetDepth/Height/Size/Width
Fixed occlussion query support not correctly setted

src/Nazara/Renderer/ShaderImpl.hpp

@@ -47,9 +47,6 @@ class NzShaderImpl
 
 		virtual void Unbind() = 0;
 		virtual void Unlock() const = 0;
-
-	protected:
-		virtual bool UpdateVertexBuffer(const NzVertexBuffer* vertexBuffer, const NzVertexDeclaration* vertexDeclaration) = 0;
 };
 
 #endif // NAZARA_SHADERIMPL_HPP