1. Written tutorial for people wishing to learn how to write xml     (jrb)
   descriptions of alternate detectors.

2. Make separate package for (geometry only?) xml files.            (jrb)
   Reorganize physical file organization slightly so that
   top file merely includes others with the actual content.

3. Entity resolver in XML package to                                (jrb)
       - allow use of environment variables in file specs
       - keep track of file versions

4. Complete definition of new IGeometry interface (to include       (rg,mf)
   access to constants and materials).  (Do we also need to do
   something about IDmapBuilder, or is this already covered 
   by the new visitor-like interface?)  Refactor detModel 
   to support IGeometry directly.

5. G4Generator                                                      (rg,mf)
         - revise for new geometry interface
         - fill hits and mc truth

6. Modify instrument to use detModel services rather than IFile to
   fetch remaining constants, or maybe don't bother with this and 
   go on to..

7. Get rid of instrument package altogether?
     what services does instrument now provide which must be provided
     some other way?
     What about ID conversion?  Do we need it?

8. HepRepSvc                                                        (rg,mf)

9. Fred (C++ HepRep client)                                         (rg, mf)

10. GDDBrowser                                                      (rg, mf)

11. Update Materials Summary and Overlap Checker diagnostics to      (jrb)
    use new interface.  Probably move from detCheck package to
    detModel (or GlastSvc?)

12. Simple XML doctype to handle job-options-type parameters
    for packages.