Contrary to what the ruby documentation says, sending a signal
to PID 0 actually signals the whole process group, not just the
current process. So use Process.pid to make sure we only signal
the current process.
Use a preinitializer to load the settings from application.yml so
that they are available as early as possible. All settings can also
be overridden using environment variables.
The ad-hoc settins in environment.rb are then moved to this new
system so we have one consistent location for settings.
