- added a clipping rectangle to DCanvas that can be used independently of DrawTexture calls.

Currently this is only being used for draw operations that are not automap related, i.e. DrawLine, DrawPixel and FillSimplePoly are not subjected to it.

src/menu/menu.cpp

@@ -279,6 +279,7 @@ void DMenu::CallDrawer()
 	{
 		VMValue params[] = { (DObject*)this };
 		GlobalVMStack.Call(func, params, 1, nullptr, 0, nullptr);
+		screen->ClearClipRect();	// make sure the scripts don't leave a valid clipping rect behind.
 	}
 }