Buyingstore persistency

Basic features of @autotrade persistency now also available for buyingstores.
Minor bug fix

If a player did not meet the requirements to reopen the buyingstore/vending for whatever reason the character is now set offline.

A possible examples I have tested with is to change the area where the player's shop was to novending, which will not allow him to open the shop in this area.
Buyingstore persistency Beta

Changed the loading process to clean up if there are some leftovers(corrupt tables).

Modified the loading query to also take in the zeny limit as criteria, since it would not make sense to set up an autotrader that already has reached his limit(this case should not be possible, if you do not modify the values in your MySQL table by hand).

Enjoy and do not forget to run the upgrade .sql files.