Added a very basic powerdns-integration script

Added a very basic powerdns-integration script written in php. Only
lists domains at this point, doesn't support TSIG (don't use them
myself) or anything else fancy. Server name & ip has to be set
manually. But works and gets jschlyter of my back (for now). ;)
Nicer looking license.
Merge pull request #4 from rickarddahlstrand/master

Added a very basic powerdns-integration script written in php.