[syslinux] Function key menu patch

[Gordon Schumacher]

I sent this a few days ago, and it doesn't seem to have showed up in the
archives... so I'm resending.

I've written a patch to syslinux-3.60-pre2 to add gfxboot-like function
key submenus, without the ugly pseudo-PostScript scripting nightmare.  :)

It still needs some debugging - it gets slightly confused if you hit a
function key assigned to a submenu if you're already displaying one, or
if you're editing the command line - but it's fairly usable.

The documentation for the new keywords is added into README.menu by the
patch.

Please let me know what you think!  (I'm not posting the patch itself 
here, since it's nearly 35K.)

http://www.valleyhold.org/~gordons/syslinux-optmenus.diff