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/Entity.h

@@ -197,6 +197,7 @@ public:
 
     //Trophy Text
     int trophytext, trophytype;
+    int oldtrophytext;
 
     //Secret lab scripts
     int altstates;