Add a unified cross platform OpenGL core profile binding (#52)

source/Irrlicht/CNSOGLManager.h

@@ -54,6 +54,9 @@ namespace video
 		//! Change render context, disable old and activate new defined by videoData
 		bool activateContext(const SExposedVideoData& videoData, bool restorePrimaryOnZero) _IRR_OVERRIDE_;
 
+		// Get procedure address.
+		virtual void* getProcAddress(const std::string &procName) _IRR_OVERRIDE_;
+
         // Swap buffers.
         bool swapBuffers();