major MDI changes

[Jaka Mocnik <jaka mocnik kiss uni-lj si>]

apart from taking the liberty of adding GnomeMDIGenericChild class
to the ever growing number of things in libgnomeui, I've also
degraded some signals in GnomeMDIClass to mere function members of
GnomeMDI (and in effect added some API changes to make things look
more uniform).
I've also changed ALL the GnomeMDIChild signals to "virtual" functions.

Now this will probably break each and every application using MDI, but
I guess it's better now than later ;) the ChangeLog entry explains most
things that have changed, any further questions should go to my email
rather than the lists, as they are pretty stuffed these days. 
I expect to have screwed up some things, so I'd appreciate bug reports
(and possible fixes ;)) from people using MDI (gtop & balsa in
particular).

regards,
	jaKa

-- 
email: jaka.mocnik@kiss.uni-lj.si
w3:    http://pluton.ijs.si/~jaka