Fix for merchant price bugs

[ChaosSlayer]

i was under impression, that 'salerate' was some sort of an option to set a custom sell back for each specific item - could realy be usefull in order to create items which would sell back for 100% base price (i can think for dozen fo reason for having such items) - or at least its the only logical explation that coudl posibly fit the description of the field name.

of course the thing never worked, so... =)

but it would be nice to have it actualy working this way =)
(could also be interesting to have item which would sell back for ABOVE base price - again for various reasons) =)