When changing navigation type from Points to Cubes, or vice versa, and then...

When changing navigation type from Points to Cubes, or vice versa, and then back to the original type, qnet will no longer re-filter all of the data, but use the old list of filtered data to populate the list of data items. Fixes #2144.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@6198 41f8697f-d340-4b68-9986-7bafba869bb8