Fixed Gui.cpp where internal defaults were not being accurately represented in...

Fixed Gui.cpp where internal defaults were not being accurately represented in the history using -last using the commandline or the arrows in the GUI. Fixes #805.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@6783 41f8697f-d340-4b68-9986-7bafba869bb8