Add dnsmasq

[bnordgren]

It should be possible to refer to the polaric webserver by a human friendly name. (like the web interface for netgear routers is routerlogin.net.) This may also help other wireless clients like APRSdroid find the aprsd instance running on the aprs-box.

This does assume that nothing else on the network is handling DNS or DHCP, so one might need to disable the DHCP function in a typical home wifi router.