Functions in zp50_items.inc

Function Description
zp_items_register
Registers a custom item which will be added to the extra items menu of ZP.

Note: The returned item ID can be later used to catch item
selection events for the zp_item_select_() forwards.
zp_items_get_id
Returns an item's ID.
zp_items_get_name
Returns an item's name.
zp_items_get_real_name
Returns an item's real name (used when registering the item).
zp_items_get_cost
Returns an item's cost.
zp_items_show_menu
Shows menu with available extra items for player.
zp_items_force_buy
Forces a player to buy an extra item.
zp_items_menu_text_add
Appends text to an item being displayed on the extra items menu.
Use this on the item select pre forward.
zp_fw_items_select_pre
Called when determining whether an item should be available to a player.

Possible return values are:
 - ZP_ITEM_AVAILABLE (show in menu, allow selection)
 - ZP_ITEM_NOT_AVAILABLE (show in menu, don't allow selection)
 - ZP_ITEM_DONT_SHOW (don't show in menu, don't allow selection)
zp_fw_items_select_post
Called after a player selected an item from the extra items menu.