Move returning to lab to separate variables

Again, what I've done here is removed the over-reliance on Terry's State
Machine to return to the lab, and just moved it into separate variables
instead. This means that returning to the lab is ALMOST entirely
self-contained in MAPMODE, except there's a quick jaunt over to GAMEMODE
to run a script because you can only run scripts in GAMEMODE.

desktop_version/src/Game.cpp

@@ -372,6 +372,8 @@ void Game::init(void)
 
     fadetomenu = false;
     fadetomenudelay = 0;
+    fadetolab = false;
+    fadetolabdelay = 0;
 
     /* Terry's Patrons... */
     superpatrons.push_back("Anders Ekermo");