boot system and buildkernel - Additional work
* Make boot <directory> work. Note however that dloader does not preload
the kernel+modules so basically all you get here is the kernel and acpi
with the current menu system setup.
The dloader way (for the moment) is:
cd kernel
loadall
boot
* Fix console=<blah>. dloader was not mirroring the variable to the
environment. Also do the same for currdev, loaddev, and bootfile.
(kernelname and module_path were already mirrored).
* Fix non-numeric menus. 'a' (kernel.alt), 'b' (kernel.bak),
and 'R' (reboot).
* Space now halts the countdown.
* Add the boot-without ACPI option back into dloader.menu.
* Move the handling of the kernelname kenv variable out of machine
specific code and into kern/init_main.c