TG: Added two new variables, "canstun" and "canweaken". They can be modified in

runtime to prevent mobs from ever being weakened and stunned by
tasers/batons/electrified doors.

Xenos are immune to stunning and weakening. This basically means you cannot run
up to a xeno and shoot them with a taser and game over. This makes them a lot
more dangerous. To compensate, I've added in a xeno-exclusive variable
controlling movement delay addition. When a xeno is stunned, its movement speed
goes down. The speed is recovered in the life() proc.

Modifications to critter.dmi (manhacks). Added a new lighting icon, floor
lights. Possible implementation later. r2886

code/defines/mob/living/carbon/alien.dm

@@ -13,4 +13,9 @@
 	alien_talk_understand = 1
 
 	var/obj/item/weapon/card/id/wear_id = null // Fix for station bounced radios -- Skie
-	var/has_fine_manipulation = 0
+	var/has_fine_manipulation = 0
+
+	var/move_delay_add = 0 // movement delay to add
+
+	canstun = 0
+	canweaken = 0 // aliens cannot be stunned or knocked down. Massive buff!

code/defines/mob/living/carbon/metroid.dm

@@ -19,6 +19,11 @@
 
 	see_in_dark = 8
 
+	// canstun and canweaken don't affect metroids because they ignore stun and weakened variables
+	// for the sake of cleanliness, though, here they are.
+	canstun = 0
+	canweaken = 0
+
 	var/amount_grown = 0// controls how long the metroid has been overfed, if 10, grows into an adult
 		// if adult: if 10: reproduces
 	var/powerlevel = 0 	// 1-10 controls how much electricity they are generating