[AD] Adding a d_subdialog_proc

[Ryan Patterson <rpatters@xxxxxxxxxx>]

I don't know what the general feeling towards the Allegro GUI is right now, 
but I'd like to propose a d_subdialog_proc addition to it. This would 
basically allow users to add one to their DIALOGs, with the dp pointer 
pointing to a DIALOG* (in otherwords, dp is a DIALOG**, not a DIALOG*, but 
either way would work)

The function would start a dialog player and distribute messages to its 
children. A message could be sent when the dp pointer changes.

The idea behind this proc is to allow easily changed areas of a DIALOG. My 
application, for instance, Will have an array of buttons during the game, but 
some informational text and a Start Game button before the game.

What do you think of this suggestion?
-- 
Regards,
Ryan Patterson <mailto:rpatters@xxxxxxxxxx>