fixed sort key calculations. the postgres driver puts ' ' around the bind variable. the old code performed calculations like "and sort_key = (:prev_sort_key + :next_sort_key)/2", which caused postgres to barf. this calculation is now done in tcl.
Initial commit of admin directory. All subdirectories in admin have been ported with the exception of products/add-4-postgresql.xql. Dynamic queries have not been ported yet. Files in the root directory of admin have not been ported yet.
