Integrating EggMenu code into GTK+

[Owen Taylor <otaylor redhat com>]

We need a volunteer to work on integrating the new menu
system from Egg into GTK+; I think the subtasks are:

 - Do the sed-job and GTK+ Makefile.am changes to
   move the code into GTK+

 - Write API docs, including documentation of the
   EggMenuMerge XML format.

 - Show off the new API in gtk-demo

These don't all have to be done in one go; the code
can first be added to GTK+, then API docs written,
and then gtk-demo enhanced.

Other notes:

 - James points out that egg-markup.[ch] should not
   be included; they have been replaced by
   egg-menu-merge.[ch]

Regards,
					Owen