Improvements to the startup script:

- Add option to not start BT.
  Defaults to starting BT.
  Disable it in /etc/default/steward
- Don't spit out errors when stopping steward
  and BT if they have not been started.
Default to start BT, for real this time.
Merge pull request #221 from torkelsson/init

Improvements to the startup script (second try)