shop changes

Date:Tue Nov 12 23:58:20 2002
Summary of changes:

 - Similar items are grouped together and sorted by price.
 - Items are divided by type, wear position, weapon type
    and various keywords for clothing and shields.
 - Shop numbers are constant until the shop closes.

 - Shopkeepers no longer have an infinite supply, but they
    will produce plenty of food, drink and missiles.
 - Shop inventories regenerate over time.
 - Detect magic is now useful when viewing shop inventories.

 - You can search for clothing by wear position, and you can
    list weapons by their types.
 - Plurals work while listing shop items (e.g. longswords)

 - You can buy up to 20 items at once.
 - You can consider objects for sale with the 'show' command.
 - Colourable items can be dyed with the immediate command 'dye'.

 - You can sell or value up to 10 items at a time
 - You can now value a receipt to find out how much time is left.
 - Shopkeepers will occasionally wear items that you sell.

 - You cannot mend brand-new items any more.
 - There is a new immediate command called 'resize'.