Previously, we were also considering the time spent in
soft-hibernation.  If this was a long time, we would wind up
underestimating our bandwidth by a lot, and skewing our wakeup time
towards the start of the accounting interval.

This patch also makes us store a few more fields in the state file,
including the time at which we entered soft hibernation.

Fixes bug 1789.  Bugfix on 0.0.9pre5.