Add %b parts per billion, Better exit statuses, Fix a few bugs

In more detail:
- Add new parts per billion CPU time usage as %b; Update configs/cb0/style.auser to use it.
- Give 2 new ways to test for existence of any matches:
- pf -e STUFF || start-it
- pf -ac STUFF >/dev/null || start-it
Fix:
- bug converting delay TimeSpec from seconds to jiffies
- Fix longstanding environ 'e' masks %cPU 'e' bug