Windows menu

Hi!

While doing squeak there are many times, where I need to find out how
something works and I end up with a pile of windows of senders,
inspectors, implementors ...
After that the new windows menu is a good place for me to find where I
left off on my journey through the system. I just thought the windows
menu could do a
little more to support this kind of workflow by:

- containing every visible window (collapsed or not)
- showing a collapsed window in the list by putting () around the label
- showing a touched window by putting a leading * to the label
- grouping windows by model (eg. Browsers are most likely always at
the top of the list)
- having a "close all like this" menu entry to close all windows of a
same kind (eg. close all open inspectors) [won't touch any windows
with changed content]
- having a "close all but this" menu entry which does exactly like the
above, but without closing the selected window

Alex