Changed map chair bonus healing mechanic to be a player skill, instead of promptly available for all players (healing buff takes place only if the player has the skill). Hired Merchant now properly checks for a space on the inventory before permitting a player to buy an item/bundle. Minor fix with concurrency on MapleStorage.
Added buff icons for active coupons the player has. Fixed a minor issue,
introduced on the last commit, that prevented coupons to become active
automatically.
