IPCE to ISIS documentation/removal of deprecated code for WorkOrder/Directory...

IPCE to ISIS documentation/removal of deprecated code for WorkOrder/Directory classes.  This commit is for both of them because of their inter-dependency so it will not break IPCE.  Fixes #3956, #3951.

git-svn-id: http://subversion.wr.usgs.gov/repos/prog/isis3/branches/ipce@6812 41f8697f-d340-4b68-9986-7bafba869bb8