Added support for OpenGL debug mode

When NzContextParameters.debugMode is true, Nazara will receive OpenGL's
debug message and send them to Nazara's log
NzString::Pointer now have the "0x" prefix
Added support for ARB_texture_storage extension
Nazara now try to load core texture 3D before trying to load
EXT_texture3D
Added NazaraNotice macro, writing raw text into Nazara's log
Added NzContext::Destroy (called in Create)

include/Nazara/Renderer/Context.hpp

@@ -24,6 +24,7 @@ class NAZARA_API NzContext
 		~NzContext();
 
 		bool Create(const NzContextParameters& parameters = NzContextParameters());
+		void Destroy();
 		const NzContextParameters& GetParameters() const;
 		bool IsActive() const;
 		bool SetActive(bool active);