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/GLSLShader.hpp

@@ -47,8 +47,6 @@ class NzGLSLShader : public NzShaderImpl
 		void Unlock() const;
 
 	private:
-		bool UpdateVertexBuffer(const NzVertexBuffer* vertexBuffer, const NzVertexDeclaration* vertexDeclaration);
-
 		mutable std::map<NzString, GLint> m_idCache;
 		mutable GLuint m_lockedPrevious;
 		GLuint m_program;