Spread Sheet improvements

In the last couple of weeks the VisAD Spread Sheet user interface
has undergone some significant changes.

First, the Spread Sheet cell resizing mechanism has been reworked,
and it now functions more like a "normal" spreadsheet application
(that is, resizing one cell no longer steals layout space from its
neighboring cells).  Hopefully the new mechanism will prove more
useful to everyone.

Second, the "spreadsheet file" support available through the
Spread Sheet's Setup menu has been greatly enhanced.  Spreadsheet
files now save most everything associated with a cell, including
the states of all associated Control widgets.  When you save a
spreadsheet to a file, then load the file later, everything should
look exactly like it did when you saved.  The spreadsheet files
are also much more robust.  You should be able to edit spreadsheet
files using a text editor (or even build them from scratch)
without any trouble.

The only drawback is that old spreadsheet files are no longer
compatible with the new format.  Fortunately, it's not difficult
to convert them to the new format; if you need instructions, just
send me an e-mail.  Also, the new format is set up so that
regardless of later improvements, old files will still be
compatible in the future.

All of these improvements are already available online within the
latest VisAD FTP distribution.  As always, feel free to e-mail me
with any questions or suggestions about the Spread Sheet.