Instead of switching targets every time their code loops, they now stick to the same target until it is incapacitated
Turrets set to stun will switch targets when their current target is lying down, because they assume it is nice and properly stunned
Turrets set to kill will switch targets when their current target is dying (or anything else that sets the stat var to 1)
The target list now properly updates if people manage to enter or leave the protected area in nonstandard ways (teleportation of tech, magic, and badmin varieties, mostly)
If turrets are turned off, they will not pop up when someone enters their area
git-svn-id: http://tgstation13.googlecode.com/svn/trunk@722 316c924e-a436-60f5-8080-3fe189b3f50e