Support postfix/sendmail

[ericclemmons]

We have to be able to notify users of password changes via WordPress, so make sure mail(...) in PHP works...

[mcheck]

@ericclemmons @EvanK
Is postfix a requirement at this point? I ask because in the current provisioning, port 25 is open to the world. I haven't worked with postfix at all, but having port 25 open seems to be a large security risk. Does it need to be open in order to only send mail outbound as intended?

[EvanK]

#71 would fix this, leaving open only ports for ssh & http/s.