vagrant: nullmailer and fakemail

[guaka]

• [ ] http://distinctplace.com/2013/06/20/nullmailer-and-fake-mail---two-little-tools-for-every-developer/
• [ ] http://sourceforge.net/projects/fakemail/
• [ ] default mailer config to reflect these so that emails in Vagrantbox (and with little effort on localhost)

cc @simison

[simison]

Docker now has MailDev installed and I recommend that for localhost development, too. Works great!