Removes most instances of item_color

Notable exception is for clothing/under, those will have to be removed once item_state override is implemented.

code/game/objects/items/weapons/implants/implant.dm

@@ -9,7 +9,7 @@
 	var/implanted = null
 	var/mob/imp_in = null
 	var/obj/item/organ/external/part = null
-	item_color = "b"
+	var/implant_color = "b"
 	var/allow_reagents = 0
 	var/malfunction = 0
 

code/game/objects/items/weapons/implants/implantcase.dm

@@ -13,7 +13,7 @@
 
 /obj/item/weapon/implantcase/proc/update()
 	if (src.imp)
-		src.icon_state = text("implantcase-[]", src.imp.item_color)
+		src.icon_state = text("implantcase-[]", src.imp.implant_color)
 	else
 		src.icon_state = "implantcase-0"
 	return

code/game/objects/items/weapons/implants/implantfreedom.dm

@@ -3,7 +3,7 @@
 /obj/item/weapon/implant/freedom
 	name = "freedom implant"
 	desc = "Use this to escape from those evil Red Shirts."
-	item_color = "r"
+	implant_color = "r"
 	var/activation_emote = "chuckle"
 	var/uses = 1.0