- 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/wi_stuff.cpp

@@ -730,6 +730,7 @@ void WI_Drawer()
 		{
 			VMValue self = WI_Screen;
 			GlobalVMStack.Call(func, &self, 1, nullptr, 0);
+			screen->ClearClipRect();	// make sure the scripts don't leave a valid clipping rect behind.
 
 			// The internal handling here is somewhat poor. After being set to 'LeavingIntermission'
 			// the screen is needed for one more draw operation so we cannot delete it right away but only here.