[RFC/RFT] calloutng

[Davide Italiano]

The patch has been splitted in smaller logical chunks in order to
improve readability and facilitate review.
The whole code can be found here:
http://people.freebsd.org/~davide/calloutng_split/

In particular:
http://people.freebsd.org/~davide/calloutng_split/sbintime.diff brings
the new type 32.32 fixed point used in lieu of 'int ticks' for the new
callout mechanism and relative functions (conversion from to
{timeval,bintime,timespec}, sbinuptime(), getsbinuptime())
This change is preliminary to
http://people.freebsd.org/~davide/calloutng_split/callout_internals.diff
which contains all the callout changes internally (introduction of
direct dispatching, conversion to sbintime, new precision mechanism)

http://people.freebsd.org/~davide/calloutng_split/cpuidle.diff  (see
r242905) introduce some optimization in the  sleep time calculation
and choose of the optimal sleep state, when CPU is idle.

http://people.freebsd.org/~mav/calloutng-20130221/libprocstatfix.diff
is a workaround in libprocstat in order to allow world to build after
changes. About this one, I'm not quite sure is the best solution, so
if there are other opinions, I'd be more than happy to hear.

Other patches available in the directory converts some kernel
consumers of callout(9) to the new interface (nanosleep, poll, select,
kqueue, syscons, etc...).

My plan is to commit the whole patchset March 4th, unless there are
valid reasons to not do so.
Any cooment is (as always) appreciated.

Thanks,

Davide