nil out CurrentHedgehog in FreeModule, add a test for nil'd CurrentHedgehog in DelCI since I'd still like to use DeleteGear for the other stuff it does. Move some variable initialiasations in AI Misc to hopefully avoid some uninit val errors.

Use FreeAndNil across the board. Even if we are immediately assigning after, probably avoids accidental mistakes. Also free neglected owner tex on shutdown, and delete hog gears using the normal deletion procedure if for any reason they still exist (EndGame call?).