Added DNSMasq DHCP lease list widget

A short time ago I set up a DNS/DHCP server on my network using DNSMasq. While troubleshooting, I found it necessary to view the list of DNS leases & wrote a short PHP script to display them. I thought it would be handy to have a widget in linux-dash that would display that information.

It looks something like this...
![temp](https://f.cloud.github.com/assets/2042984/2095754/4ed25b5c-8eef-11e3-9e46-9e8f6f3dcc1b.png)

And it includes a datatype for sorting by IP address.