Brought other organ terms into line with new general organ class.
The basic structure is now: a set of granularity terms for multicellular structures, all of which could apply to an organ.
Dual inheritance is currently asserted, but could be punted to PATO.
Also worked on anatomical system terms.  Their defs will, I think, need some more polishing.

I've also done some parallel work to add more classes and axioms to PATO for
 - (maximally) connected
 - disconnected
 - multicellular

A release of PATO + relevant imports will be needed before a CARO release.