* Remove a procedural layer in the scheduler clock code by having

* Remove a procedural layer in the scheduler clock code by having
  kern_clock call the usched scheduler clock function directly.

* Move p_estcpu to scheduler-specific code.

* Have kern_synch's one-second timer call into the scheduler instead of
  trying to figure it out itself.

* Decay p_estcpu whenever a user process is scheduled as well as once
  per second, leading to (hopefully) better performance under load and
  better handling of adverse conditions (a nice +20 process running in the
  face of a nice -20 process).

* No longer assume that one second has elapsed in the one-second callback.
  Instead calculate the elapsed time on a per-process basis.  This should
  reduce instances of batch processes 'glitching' interactive processes.

* Remove the old round-robin code and instead just have the scheduler
  figure it out internally in the scheduler clock function.

* Revamp the scheduler algorithms, making everything #define constant
  driven.  Retain the NICE-based base-priority and decay algorithms but
  narrow the decay range from the process nice value.  Retain the child
  estcpu inheritance algorithm.

Feedback-provided-by: walt <wa1ter@myrealbox.com>