- removed DFrameBuffer's locking mechanism.

In its current form this is quite useless. What's really needed is to require a lock on the RenderBuffer for the 3D scene, but since this is not needed for the 2D stuff anymore it can be done far simpler.

src/gl/system/gl_framebuffer.cpp

@@ -178,7 +178,6 @@ void OpenGLFrameBuffer::Update()
 	GLRenderer->Flush();
 
 	Swap();
-	Unlock();
 	CheckBench();
 
 	int initialWidth = IsFullscreen() ? VideoWidth : GetClientWidth();