PROG: Added @history/@internal/@author Doxygen tags to...

PROG:  Added @history/@internal/@author Doxygen tags to GuiCameraDisplayProperties::XmlHandler class.  createReleaseNotesXML script was issuing PHP warnings.  References #4018

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@6806 41f8697f-d340-4b68-9986-7bafba869bb8