Make Geom::find method public
Make Geom accessor methods const
Encode geometry info via detector ID

Replace old-style east/west and "NSTB" convention.
Uses detector ID values in the database.
Return float from Geom functions

Replace pointer returns with values - prevents having to test for valid
pointers (which was never done anyway!).

Rename ZFPD() to z().
Rework tower width function

Rename Geom::FpdTowWid to Geom::towerWidths.
Change return type from float array to float vector.
Remove now-unused Geom::FMSGeom
Require explicit initialization of Geom

Doing so, rather than (trying it) in the constructor allows us to test
for errors in initialization and return an error from InitRun in the
maker in case of problems.

Rework StFmsPointMaker::InitRun() accordingly.
Tidy up headers in Geom

Remove unused, add those used but not explicitly included
Put Geom source code in namespace

Also remove ClassImp statement, not required
Add Doxygen comments to Geom header