Add more details to log when an event was received.
Merge branch 'master' into mm-improve-logging

Conflicts:
	lib/travis/listener/app.rb
Enable debug temporarily.
Fix logged details for pull requests.
Log only 7 char shas.
Log head commit and commit ids properly for push.
Fix log payload.
Bump log level back to info.
Merge pull request #9 from travis-ci/mm-improve-logging

Improve logging