Enlarge.h: 2011-08-19 Jeannie Backer - Modified unitTest to use $temporary...

Enlarge.h: 2011-08-19 Jeannie Backer - Modified unitTest to use $temporary variable instead of /tmp directory. Added some documentation to methods. 
unitTest.xml: Replaced test cube path /tmp/... with $temporary/... 

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@3065 41f8697f-d340-4b68-9986-7bafba869bb8