Yeets Prommies from antag (#370)

They're simply too powerful. We're too unrobust to deal with the absolute heck of antag prommies. This is a better solution than well, just /removing/ them

code/game/antagonist/antagonist.dm

@@ -4,7 +4,7 @@
 	var/list/restricted_jobs = 		list()   // Jobs that cannot be this antagonist at roundstart (depending on config)
 	var/list/protected_jobs = 		list()   // As above.
 	var/list/blacklisted_jobs =		list(/datum/job/submap)   // Jobs that can NEVER be this antagonist
-	var/list/blacklisted_species =   list(SPECIES_ADHERENT, SPECIES_DIONA, SPECIES_NABBER)
+	var/list/blacklisted_species =   list(SPECIES_ADHERENT, SPECIES_DIONA, SPECIES_NABBER, SPECIES_PROMETHEAN)
 
 	// Strings.
 	var/welcome_text = "Cry havoc and let slip the dogs of war!"