Heads Up - Modeless dialogs coming.

[Martin Sevior]

Hi everyone,
            well after some major fights with the gtk_main loop but mostly
my own stupidity I've got a basic framework for modeless dialogs working
and have converted "Insert Symbol" to modeless. I can put in stubs into
the windows, qnx, beos and mac front ends so they compile but they won't
work of course.

Would people like to see to a patch before I commit? I'm quite happy with
it for the gtk front end.

Cheers

Martin