Interpolate trophy text

Just to make sure it's extra smooth. Not that it will be noticeable, and
you can't access the Secret Lab in slowmode without modifying the game,
but it's nice to have this.

desktop_version/src/Logic.cpp

@@ -247,6 +247,8 @@ void gamelogic()
         obj.upset = 0;
     }
 
+    obj.oldtrophytext = obj.trophytext;
+
     if (map.towermode)
     {
         if(!game.completestop)