Base our expected bw accounting usage on time before soft limit
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.