Improved user interface for the new sorting options to be (hopefully)...

Improved user interface for the new sorting options to be (hopefully) extremely obvious what the options are, how they work, and why your tables are not sorting (when they aren't sorting). Fixes #838.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@4448 41f8697f-d340-4b68-9986-7bafba869bb8