Replaces sendmail with direct

Closes #1538
* rips out sendmail
* adds direct
* updates nodemailer to 0.7.1
* changes unit tests for mail
* changes integration tests for mail
* adds api tests for mail
If it does get to the eventuality that it won't be sent, it will trigger the "failed" handler, right? I don't think this message is necessary, unless it can get stuck in a "requeue" loop