menu enchancement

["Yoshinori K. Okuji" <okuji@enbug.org>]

I've implemented some important features in the menu interface. That is, 
timeout and booting. Please test it. It should be now possible to boot 
an OS from the menu interface.

However, there are still several missing features which can be found in 
GRUB Legacy:

- Editing a boot entry

- Password

- Multiple fallback entries

- Saving a boot entry

- Coloring (this is useless, IMHO)

But one good thing is that GRUB 2 supports nested menus, although this 
is not usable until we implement the command "configfile".

I wish to see these features:

- Graphical interface

- Support for different geometries

- Message translation

Probably support for different geometries is difficult, because the 
current code assumes that the screen is at least 80x25. If you want to 
support smaller one, you need to adjust the messages as well as the 
hardcoded coordinates.

Next, I will work on editing a boot entry and password support.

Okuji