WinHugs, Toolbar patch

[Neil Mitchell]

Heirarchy shows the class constraint heirarchy. Its kind of useful,
but not very often, since it rarely (if ever) changes. For your info,
a screenshot is here:
http://www-users.cs.york.ac.uk/~ndm/temp/heirarchy.png

Edit is pretty useless, it invokes the editor with Hugs.Base, a file
you probably have no wish to change at all. After invoking edit, you
then need to create a new file and save it somewhere in your text
editor. Because you already opened Hugs.Base, your editor has changed
directory to the Hugs libraries, a bad place to store your work! Its
faster to invoke your text editor directly, and probably less
dangerous (people can easily overwrite Hugs.Base this way). Edit is
still provided for the documents you load, via hyperlinks, and that is
incredibly useful.

Between me and the 2 other people I know who use WinHugs, none of us
have ever clicked on the edit button. If it turns out there is a class
of user who does use edit, I'll put it back.