Csurf "session:" entry/dropdown (right)

This entry contains the current session.  The
dropdown contains a list of all the sessions in
the current $FUNCTIONALS_DIR, typically with
chronologically-sorting names (avoid spaces!):

  120827MS

Selecting a session from this dropdown is
equivalent to File -> Open Functional.

Selecting a session from the sessions dropdown
automatically looks up the matching subject in
the current $SUBJECTS_DIR (using the "name" file
in this session), and sets the "subject:" field
to that subject (if found).

Entering text plus <Return> here pops up a list
of partial matches.  Glob-style patterns (* for
anything including nothing, ? for a single
character) can be used to narrow search (but are
not required).  If the suggested session-naming
convention above has been followed, simple
searches by date or subject can quickly be
performed:

 MS		all sessions containing "MS"
 12*MS		all 2012 sessions on MS
 1206????		all June 2012 sessions

All the sessions in $FUNCTIONALS_DIR are loaded
at csurf startup time.  To update the dropdown if
a session has been added after starting csurf,
use File -> Update Subjects/Sessions or Cmd-u
(Mac) or Alt-u (Linux).

Since the csurf program stores configuration
information for the current subject in:

  $FUNCTIONALS_DIR/<sess>/image/scripts/csurf.dat

it will complain if you try to select a session
directory in $FUNCTIONALS_DIR that does *not*
contain a "scripts" subdirectory (in the image
subdirectory).
