There is not documentation for sortable tables at the current time.
You make a table sortable by giving it the vw-sort-table class.
The script should automatically figure out what kind of sorting to use for each column, but you can override this behavior by giving each heading one of the following classes:
vw-sort-none (don't sort this column)
vw-sort-alpha (alphabetically)
vw-sort-ddmm (by date in day/month format)
vw-sort-mmdd (by date in month/day format)
vw-sort-numeric (numerical order)
The default sort of the table will be the order that it is defined in the source (read: unsorted). It will only be sorted when the user clicks one of the headings.