exit warps back to the same room, clicking on the same exit again is
misinterpreted as a double-click, and that only works if we're already walking
towards that exit. Otherwise, the game will hang. This fixed bug #1851502
("SWORD2: Black-out in Forest").
svn-id: r29876
that these are stopped whenever the engine is going to do a mass killing of
game resources, e.g. when restoring or restarting the game. Should fix bug
#1645480. (This was a regression added during the rewrite to support DXA.)
svn-id: r25204
