Adds a cursed sword (and other haunted things) (#4931)

* adds cursed sword and 'haunted' object framework.

* fixes back.dmi conflicts

* adds cursed blade ghost pod

as well as fixing some ghost pod oddities

* fixes misc.dm conflicts

* adds cursed sword cave POI

* makes cursed sword use voice mob

as opposed to a brainmob

code/datums/ghost_query.dm

@@ -132,3 +132,9 @@
 	question = "A curious explorer has touched a mysterious rune. \
 	Would you like to play as the creature it summons?"
 	cutoff_number = 1
+
+/datum/ghost_query/cursedblade
+	role_name = "Cursed Sword"
+	question = "A cursed blade has been discovered by a curious explorer. \
+	Would you like to play as the soul imprisoned within?"
+	cutoff_number = 1