Send e-mails using Gmail Python module instead of SMTPlib

[dotbugfix]

Using SMTPlib in Python with the Gmail server has multiple problems:

1. The user has to type in their username/password in WittyMail (so we can access it or log it)
2. In Gmail settings, the user needs to 'allow access to insecure apps'

This is an undesirable experience. Once we implement login using Google OAuth, we should be able to use the same token to send emails and not have to do 1 or 2 above.