Adds a option to config.txt called PROTECT_ROLES_FROM_ANTAGONIST.

If PROTECT_ROLES_FROM_ANTAGONIST is set, sec/hos/captain/AI cannot be antagonists in most modes
If it is not set, only jobs that are mutually exclusive to the role (sec/head during rev, etc) are immune from being antagonist

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@3225 316c924e-a436-60f5-8080-3fe189b3f50e

code/datums/configuration.dm

@@ -31,6 +31,7 @@
 	var/del_new_on_log = 1				// del's new players if they log before they spawn in
 	var/feature_object_spell_system = 0 //spawns a spellbook which gives object-type spells instead of verb-type spells for the wizard
 	var/traitor_scaling = 0 //if amount of traitors scales based on amount of players
+	var/protect_roles_from_antagonist = 0// If security and such can be tratior/cult/other
 
 	var/list/mode_names = list()
 	var/list/modes = list()				// allowed modes
@@ -231,6 +232,9 @@
 				if ("traitor_scaling")
 					config.traitor_scaling = 1
 
+				if("protect_roles_from_antagonist")
+					config.protect_roles_from_antagonist = 1
+
 				if ("probability")
 					var/prob_pos = findtext(value, " ")
 					var/prob_name = null