GroundGrid.h: 2011-01-26 Steven Lambright Fixed a bug where the grid was not...

GroundGrid.h: 2011-01-26 Steven Lambright Fixed a bug where the grid was not consistent on the edges and added SetGroundLimits and WalkBoundary for the new grid options Bound lat/lon range. 

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@1644 41f8697f-d340-4b68-9986-7bafba869bb8