Fixed a "feature" in pc_system.cc with setting timers to small values
that can cause bochs to hang.
Significantly improved the performance of the new PIT.
It's probably ready to become the default now.
Added a preliminary implementation of the slowdown timer
that Bryce and I had talked about.
Also added a hack to keep the OpenBSD timer problem from filling the log.
The new PIT seems to work, but until some
enhancements are made to the way the timers
and devices.cc work, it'll be slower than
the old one.
