Replaces /image with /mutable_appearance (#556)

* Replaces /image with /mutable_appearance, where appropriate

* Update miscellaneous.dm

* Delete miscellaneous.dm.rej

* Delete pet.dm.rej

* Update pet.dm

* Update species.dm

* Update miscellaneous.dm

* Update species.dm

* Update miscellaneous.dm

* Delete species.dm.rej

* Update species.dm

pretty sure I got all the indentation correct THIS time, ffs

* Update species.dm

* Update species.dm

fucking tabs man, fucking tabs.

code/game/objects/items/weapons/pneumaticCannon.dm

@@ -162,5 +162,5 @@
 	src.cut_overlays()
 	if(!tank)
 		return
-	src.add_overlay(image('icons/obj/pneumaticCannon.dmi', "[tank.icon_state]"))
+	add_overlay(tank.icon_state)
 	src.update_icon()