Split onground/onroof into visual and logical variables

I will need to separate these into two different variables because I
will need to move logical onground/onroof assignments to the start of
gamelogic() - if I kept them together, however, that would change the
visuals of onground/onroof, which I want to keep consistent with 2.2.

desktop_version/src/RenderFixed.cpp

@@ -45,6 +45,9 @@ void gamerenderfixed(void)
                 obj.entities[i].onroof--;
             }
 
+            obj.entities[i].visualonground = obj.entities[i].onground;
+            obj.entities[i].visualonroof = obj.entities[i].onroof;
+
             //Animate the entities
             obj.animateentities(i);
         }