Finished jobs have to send a status email to the mailing list (#45)

This is for issue #45.
I configured the jobs to send emails, similar as we do on mozmill-ci. Make different reg-ex for the mail subject, and I tested it on staging node, because from local node it can't send emails through mozilla smtp server (smtp.mozilla.org)
This it will take the default email subject and status form:
https://github.com/mozilla/coversheet/pull/50/files#diff-c567af5a6d17cb8b33d678dff0d777a1R125 
I'll forward you some of emails from the time I made the pr, beside that I'll update the email adres .