Fix issues with dropping scenario into existing map

If you create a new map, and then drop the scenario code into the new map (load/save on client, since headless will wipe out control.lua when doing this), the scenario doesn't load properly.

Various parts of the scenario were created without thought about dropping them into an existing map, and player 1 doesn't initialize correctly (in a single-player state).

The scenario code needs some investigating to see what can be alleviated here. There may not be any events to catch in the particular example above, but it's worth a look.