Adding vagrant support

Vagrant will provide you with a default devel box where code
can be tested. No further arguments like "On my system it is
running. Has to be yours".
I choosed a Debian wheezy based box with saltstack installed.
Wheezy because it is stable and ships mostly older packages
than other distros. Saltstack is used for pre-installing
packeges when bringing up our box. So any requierements from
fail2ban can be saved here and shipped out with git.

You can add multiple other boxes. For example adding CentOS
to check if the tests are passing also there.