PROG: Merging IPCE classes SpiceRotation/Target into ISIS. Unit tests and...

PROG:  Merging IPCE classes SpiceRotation/Target into ISIS.  Unit tests and documentation to follow.  This is to unblock ticket #3997.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/trunk@6803 41f8697f-d340-4b68-9986-7bafba869bb8