sales, percentages and coupon improvements for MarketPress

- Sale Price: does this field take an amount or a percentage? (I guess it is an amount)

- would it make sense to be able to enter a % in the sale price field too?

- how about being able to tie the sales price to a date range after which it simply gets reset? useful for winter sales for example

- how about being able to create coupons for certain categories, i.e. a 10% discount on all products in my ladies underwear category?

- how about the ability to mark coupons so they only work on the normal price not on the sales price and vice versa?