Viruses no longer re-infect people who have been vaccinated or otherwise cured.

Chameleon projectors no longer let you move freely in space.
- I realize the way I fixed this is terrible, but the whole relaymove() proc in chameleon projectors is terrible. I was unable to rewrite it without breaking it completely so this fix will have to do.

Runtime fix for facehuggers having a null target (the mob they're attacking.)

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@3930 316c924e-a436-60f5-8080-3fe189b3f50e

code/game/objects/alien/facehugger.dm

@@ -163,7 +163,7 @@ var/const/MAX_ACTIVE_TIME = 600
 		return
 
 	proc/Impregnate(mob/living/carbon/target as mob)
-		if(target.wear_mask != src) //was taken off or something
+		if(!target || target.wear_mask != src) //was taken off or something
 			return
 
 		if(!sterile)

code/game/objects/devices/chameleonproj.dm

@@ -23,6 +23,8 @@
 		..()
 		master.disrupt()
 	relaymove(var/mob/user, direction)
+		if(istype(loc, /turf/space)) return //No magical space movement!
+
 		if(can_move)
 			can_move = 0
 			switch(usr.bodytemperature)

code/modules/mob/mob_cleanup.dm

@@ -9,9 +9,11 @@ Put (mob/proc)s here that are in dire need of a code cleanup.
 /mob/proc/contract_disease(var/datum/disease/virus, var/skip_this = 0, var/force_species_check=1)
 //	world << "Contract_disease called by [src] with virus [virus]"
 	if(stat >=2) return
-	if(virus.type in resistances)
-		if(prob(99.9)) return
-		resistances.Remove(virus.type)//the resistance is futile
+
+//This gives a chance to re-infect cured/vaccinated mobs
+//	if(virus.type in resistances)
+//		if(prob(99.9)) return
+//		resistances.Remove(virus.type)//the resistance is futile
 
 	for(var/datum/disease/D in viruses)
 		if(istype(D, virus.type))