The Rackspace Cloud DNS provider for Denominator.

Here's initial support of the Rackspace Cloud DNS provider for Denominator. It's pretty much read only at this point but I wanted to get feedback before going any further.

Right now it's working with org.jclouds.labs:rackspace-clouddns-us:1.7.0-SNAPSHOT ( there is no 1.6.0-SNAPSHOT, see https://oss.sonatype.org/content/repositories/snapshots/org/jclouds/labs/rackspace-clouddns/ ) but when jclouds-1.6.0-rc.5 is out, I'll test it against that. Eventually it will depend on jclouds-1.6.0.

Let me know what you think.