Fix Watchdog not always removing the instance directory
Lower server instance dir toucher interval from 6 hours to 1 hour, which hopefully prevents problems with a wider range of tmp cleaners
Remove forgotten debugging code
Revamp logging levels

Introduce notice and info levels.
Major fixes and cleanups

- Fix agents starter
- Get rid of passenger_tmpdir
- Replace ServerInstanceDir with InstanceDirectory
Remove support for Rails 1.2-2.2