DNS Extension 2.0 Reimplementation

This pull request marks a complete reimplementation of the DNS extension. Changes to the RubyDNS API (of which this extension depends upon) broke everything. Fortunately, it was for the better since reimplementing the extension to utilize the new 0.7.x API makes it much more stable, secure, and easier to maintain.

It should be noted that support for HINFO, MINFO, and TXT resource records have been dropped. There is no foolproof way to validate the responses for them and seeing as BeEF has no real use for them, it did not make sense to keep them around. TXT may have use in the future and can be brought back in (securely) if need be.

Unit and integration tests remain disabled. They have not yet been updated to use the new API. They should not be left like this for long.