Staircase scheduler v8.6

Updated the staircase cpu scheduler. This version is the first in the next development phase I've been leading it towards - removing dependency on scheduler_tick to make it suitable for a tickless kernel.

v8.6 removes all timeslice expiration from scheduler_tick and does this with an on-demand timer of it's own. Currently this does not offer any major advantage over the previous version, but once more of the code is removed from scheduler_tick and there is a mechanism for more accurate timers not dependant on jiffies it will offer better accuracy, lower overhead and low power advantages.

Rolled up and split patches for 2.6.9-rc2-mm2 available here:

http://ck.kolivas.org/patches/2.6/2.6.9/2.6.9-rc2-mm2/

rolled up patch:
from_2.6.9-rc2-mm2_to_staircase8.6

is a combination of:
#back-zaphod.patch
#from_2.6.9-rc2_to_staircase8.4
#s8.4_fixhotplug.diff
#s8.4-expiration_notick.diff

Cheers,
Con

P.S. I will be offline for a week as of tomorrow.