ViewportBuffer.h: 2011-04-25 Steven Lambright - Fixed bounding rect...

ViewportBuffer.h: 2011-04-25 Steven Lambright - Fixed bounding rect calculations and fill action creation 
CubeViewport.h: 2011-04-25 Steven Lambright - Fixed "center" and added more safety checks. 
ViewportBufferFill.h: 2011-04-25 Steven Lambright Fixed a problem where 1 too few lines were being read 

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@2306 41f8697f-d340-4b68-9986-7bafba869bb8