added sortDetail object, added doc
added sortDetail object, added doc

* Sort detail was added to be able to sort the query results
  for locations.
* Added missing variable documentation.

python-fedex-devs/python-fedex,gtaylor/python-fedex,gtaylor/python-fedex,python-fedex-devs/python-fedex,python-fedex-devs/python-fedex,python-fedex-devs/python-fedex,gtaylor/python-fedex,gtaylor/python-fedex