A service used to sort the contents of a XUL widget.
Sort the contents of the widget containing aNode
using aSortKey as the comparison key, and
aSortDirection as the direction.  
ascending: to sort the contents in ascending order
  descending: to sort the contents in descending order
  comparecase: perform case sensitive comparisons
  integer: treat values as integers, non-integers are compared as strings
  twostate: don’t allow the natural (unordered state)  
| aNode | A node in the XUL widget whose children are to be sorted. | 
| aSortKey | The value to be used as the comparison key. | 
| aSortHints | One or more hints as to how to sort: |