Save and Restore are now implemented in TTriumfFileGUI (but without xml, for
now).  The save file format is simple keyword lookup, e.g.,

# this is a comment         --> comments begin with #
FILE filename               --> opens data file (.root or .hbook)
HOST hostname               --> opens online socket
GROUP groupname             --> makes group
HISTOGRAM source histname   --> puts histogram (from source) into this group
...
GROUP groupname             --> makes another group
HISTOGRAM source histname   --> puts histogram into this group
...

The case of the keywords are not important, but the order is important, in
that the source for any histograms to be inserted into a group must be
listed above the group.

The Draw Group option has been repaired, so a new canvas is always opened
and the window title contains the group name.  I still have to check that
the online histograms in this canvas are refreshed properly.

Modified the Open file menu so there is only one menu item (instead of .root
and .hbook) but the open file dialog allows you to choose the file type.