Proportional share scheduler

[Matthew Dillon]

    I am going to go ahead and commit it to the HEAD.  The diff is basically
    against just two files, all minor adjustments to bring in your new
    usched_pshare.c source file.  I'm sure some minor bugs will rear their
    ugly heads over time and we can stomp them out as they do.

    The 2-clause BSD copyright at the top of the file is fine but it has
    Peter Wemm's name in there instead of yours.  I will add your name.
    Did you just use that as a template from somewhere and Peter's name
    was incidental to the work, or was it more substantial and I also
    keep Peter's name in there?

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>