Mothership Zeta Crash Site Tweaks

Removed record edits to the alien radio world object. Its position is now handled entirely within the ufo activator script.
Removed global variable. This is now a local variable in the ufo activator script.
Added lots of sanity checking to the ufo activator script to ensure things dont run when they aren't supposed to.
No longer modifies the MZ1 quest script. This should make the mod much more compatible
More specifically: I did a very hacky workaround, I moved the alien broadcast radio to be centered on the alien ship and far below the ground. Saying yes to the message teleports the radio right below the ship, easily within the bounds for the player to be beamed up.
Updated for TTW 3.3.1