Monitor parent process to ensure cleanup

In the event that the creator of a stats_hero process dies before cleaning up
the stats_hero worker, that process can be leaked.

This patch monitors the parent process.  If the parent process goes down prior
to cleaning up the stats_hero worker, the stats_hero worker will log a message
and terminate cleanly.
PR Comments
Doc update
Merge pull request #10 from opscode/of/monitor_originating_process

Of/monitor originating process