Add support for Mailhog

[jessehs]

I believe the steps are as follows:

-- brew install mailhog
-- follow symlink instructions shown to start the service
-- in your php.ini set smtp_port=1025,
-- in your php.ini set sendmail_path = "/usr/local/Cellar/mailhog/0.1.8/bin/MailHog sendmail test@test"
-- restart apache
sent mail is now viewable at localhost:8025