Add DigitalOcean (https://www.digitalocean.com/) IP Ranges

Sourced from https://github.com/hanswolff/ipranges/blob/master/IpRanges/Resources/DigitalOcean.xml and updated with latest results from http://whois.arin.net/rest/org/DO-13/nets
Merge pull request #25 from damonmorgan/feature/digitalocean

Add DigitalOcean (https://www.digitalocean.com/) IP Ranges