Added super department filter to item maintenance.
Added dedicated webservice for looking up department related info
including department settings and lists of child departments
& subdepartments.
Changed discount to a drop down to cover permutations of discount
and line_item_discountable. Changed default value of line_item_discountable
to 1 so the drop down will normally say either "Yes" or "No" for
places no using line_item_discountable. This should be less
confusing/disruptive