TableField and related files have been brought closer to Isis3 coding...

TableField and related files have been brought closer to Isis3 coding standards. Test coverage has been improved or maintained for these files. Fixes #1169.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@4753 41f8697f-d340-4b68-9986-7bafba869bb8