Follow up 32fd3ee:
- Added config 'discount_item_point_shop' to decide item/point shop is discountable or not. (see conf/misc.conf), thx http://rathena.org/board/tracker/issue-8298-itemshop-and-pointshop/
- (for advanced use) Added optional discount flag for item/point shop. (see doc/script_commands.txt)
--> -%TAB%itemshop%TAB%<NPC Name>%TAB%<sprite id>,<costitemid>{:<discount>},<itemid>:<price>{,<itemid>:<price>...}
--> -%TAB%pointshop%TAB%<NPC Name>%TAB%<sprite id>,<costvariable>{:<discount>},<itemid>:<price>{,<itemid>:<price>...}

Signed-off-by: Cahyadi Ramadhan Togihon <house.bad@gmail.com>