Add human-readable summary based on yaml report

For cases where you don't want to expose your puppet reports on a public
service. Or when the public service stops working because you have too
many failed reports... :-/

A sample notification sent to IRC looks like this:

    Puppet stable run failed at Mon May 13 15:25:03 2013. Summary at puppetmaster0:/var/log/puppet-reports/foobar123.vserver.example.com-0.640093941855566
Merge pull request #7 from mfournier/local-file-report

Add human-readable summary based on yaml report