Rewrote cube to be faster, more efficient, and more reusable. Added the Area3D...

Rewrote cube to be faster, more efficient, and more reusable. Added the Area3D class. Updated all Cube API calls to better match what we think the standards will be. -Jai and Steven

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@2661 41f8697f-d340-4b68-9986-7bafba869bb8