New in 0.5:
* "view" dialog contains the information from the currently selected
tree item.

* Description boxes are editable.

* Edit functions know which tree node they operate on or
display error message if none is selected.

* Double clicking a tree entry pops up the "view" window.

* Only one tree node can be selected at one time.

New in 0.4:
* Small bugfix: Pure "delete event"s were having some problems with my
modal window code.

* Added "Ctl-O" as an accelerator of "Open"

New in 0.3:
* Added modal window support. (Dialog windows don't open more than once
at a time.)

* "cancel" buttons now work.

* Data file-selection window opens.

New in 0.2:
* Basic GUI functionality has been added to the main window.

New in 0.1:
* Basic layout completed. Nothing actually does anything.
