Clarify debug message about exit
Clarify debug message about server status
Fix example-master, too complicated to be useful

It was a bad version of strong-supervisor, now it's an example load
options, and basic clustering.
Size for loadOptions() allows 0, and mixed case

`0` now means a master with no workers, a useful configuration, and
strings such as "default" and "CPUs" are now matched case-insensitively.
Emit 'setSize' event after size is set

There are a number of sources of size sets (clusterctl, API,
strong-agent), this allows the changing of the set size to be observed.
Emit 'startRestart' when restart begins

This allows the currently restarting worker IDs to be observed by
strong-agent, and getRestarting() allows the current state of
restarting workers to be known.
Include master process ID in status