New Qsmtpd Version and SPF Support

Hi guys just wanted to let you know a new version of Qsmtpd has been released (v0.19), so I updated the guide and also that I included a new section for SPF.

This guide includes SPF checks with spamassassin and I posted a guide to know how to configure it for your domain so you get lower spam rates.

I also wanted to tell you that I'm wrapping up a FreeBSD installation guide. It will work for any *ix environment as it only uses tars.