initial sort (weight)

The module makes use of the tablesort functions to provide the clickable table headers. However, because it isn't doing direct SQL calls but rather making use of existing taxonomy.module functions to retrieve data, we have to do the actual sorting manually.

There is a bit of a quirk in that when you first go to a taxonomy list terms page like 'admin/taxonomy/1', the arrow next to "Weights" is pointing the wrong way. Changing the "sort" element in the table header definition has no effect on the initial display, which can cause some confusion.