#2 Add a menu display and countdown timer

[Jason Johns]

Add an option for the bootflags to display the aboot boot
menu and allow a x second countdown before booting to
the default. This would allow you to choose between 2
or more kernels/partitions/installations without having to
halt, go to the SRM console and change the bootflags.
If nothing is chosen in the alloted time, then the default
option is booted.