Action Button Update

- Refactors action button backend
   - Action buttons are no longer checked on Life(), items are responsible
     for adding/removing/updating them.
   - Item action buttons are no longer a static action_button_name define,
     items define actions_types, which is a list of paths.
   - Items can now have multiple action buttons.
     - This is handled by new arguments to ui_action_click, the first
       parameter is the user, the second is the path of the action datum
       that was invoked.
 - Refactored how internals function
   - You may now directly switch internals without breaking anything.
   - The internals icon has been updated to be more consistent.
 - Added action buttons for jetpacks
 - Added action buttons for oxygen tanks
 - Uses-based implants now qdel() themselves when they run out of uses.
   This is somewhat a buff to traitor implants, but it's such a minor
   change. The actual reasoning is so that the action buttons are properly
   removed.
 - Fixed a bug with the "Boo" spell which resulted in IsAvailable failing
   for certain ghosts.
 - You can now shift-click on movable HUD elements to reset them to the
   proper position (thank fucking christ)

code/game/objects/items.dm

@@ -29,10 +29,8 @@
 	var/max_heat_protection_temperature //Set this variable to determine up to which temperature (IN KELVIN) the item protects against heat damage. Keep at null to disable protection. Only protects areas set by heat_protection flags
 	var/min_cold_protection_temperature //Set this variable to determine down to which temperature (IN KELVIN) the item protects against cold damage. 0 is NOT an acceptable number due to if(varname) tests!! Keep at null to disable protection. Only protects areas set by cold_protection flags
 
-	//If this is set, The item will make an action button on the player's HUD when picked up.
-	var/action_button_name //It is also the text which gets displayed on the action button. If not set it defaults to 'Use [name]'. If it's not set, there'll be no button.
-	var/action_button_custom_type = null
-	var/datum/action/item_action/action = null
+	var/list/actions = list() //list of /datum/action's that this item has.
+	var/list/actions_types = list() //list of paths of action datums to give to the item on New().
 
 	var/list/materials = list()
 	//Since any item can now be a piece of clothing, this has to be put here so all items share it.
@@ -72,10 +70,17 @@
 	var/sprite_sheets_obj = null //Used to override hardcoded clothing inventory object dmis in human clothing proc.
 	var/list/species_fit = null //This object has a different appearance when worn by these species
 
+/obj/item/New()
+	..()
+	for(var/path in actions_types)
+		new path(src)
+
 /obj/item/Destroy()
 	if(ismob(loc))
 		var/mob/m = loc
 		m.unEquip(src, 1)
+	for(var/X in actions)
+		qdel(X)
 	return ..()
 
 /obj/item/proc/check_allowed_items(atom/target, not_inside, target_self)
@@ -293,14 +298,16 @@
 		return 1
 	return 0
 
-/obj/item/proc/talk_into(mob/M as mob, var/text, var/channel=null)
+/obj/item/proc/talk_into(mob/M, var/text, var/channel=null)
 	return
 
-/obj/item/proc/moved(mob/user as mob, old_loc as turf)
+/obj/item/proc/moved(mob/user, old_loc)
 	return
 
-/obj/item/proc/dropped(mob/user as mob)
-	..()
+/obj/item/proc/dropped(mob/user)
+	for(var/X in actions)
+		var/datum/action/A = X
+		A.Remove(user)
 
 // called just as an item is picked up (loc is not yet changed)
 /obj/item/proc/pickup(mob/user)
@@ -324,7 +331,13 @@
 // for items that can be placed in multiple slots
 // note this isn't called during the initial dressing of a player
 /obj/item/proc/equipped(var/mob/user, var/slot)
-	return
+	for(var/X in actions)
+		var/datum/action/A = X
+		if(item_action_slot_check(slot, user)) //some items only give their actions buttons when in a specific slot.
+			A.Grant(user)
+
+/obj/item/proc/item_action_slot_check(slot, mob/user)
+	return 1
 
 //returns 1 if the item is equipped by a mob, 0 otherwise.
 //This might need some error trapping, not sure if get_equipped_items() is safe for non-human mobs.
@@ -379,11 +392,11 @@
 	return
 
 
-//This proc is executed when someone clicks the on-screen UI button. To make the UI button show, set the 'icon_action_button' to the icon_state of the image of the button in screen1_action.dmi
+//This proc is executed when someone clicks the on-screen UI button.
 //The default action is attack_self().
 //Checks before we get to here are: mob is alive, mob is not restrained, paralyzed, asleep, resting, laying, item is on the mob.
-/obj/item/proc/ui_action_click()
-	attack_self(usr)
+/obj/item/proc/ui_action_click(mob/user, actiontype)
+	attack_self(user)
 
 /obj/item/proc/IsReflect(var/def_zone) //This proc determines if and at what% an object will reflect energy projectiles if it's in l_hand,r_hand or wear_suit
 	return 0