DELETE endpoint support added.

commit 8c8a05560baa8d80fa60afd28bec8f79e59f36cf
Merge: 28ca545 dcecbbf
Author: Samuel A. Falvo II <kc5tja@arrl.net>
Date:   Fri May 17 13:22:21 2013 -0700

    Merge pull request #2 from racker/delete-method

    Support for DELETE method and non-200 responses

commit dcecbbfa45209e3afc353ebf594e45d2790a9cb9
Author: Samuel A. Falvo II <sam.falvo@rackspace.com>
Date:   Fri May 17 13:15:22 2013 -0700

    Support for DELETE method and non-200 responses

    The Delete method adds support for DELETE requests.  Pretty basic.

    There is a new option that can be set when issuing API calls.  Some API
    endpoints return non-200 results when they succeed; for example, API
    calls which do not return a response are allowed to respond with a 204
    result code.  To support this without thinking it's an error, the
    OkCodes field may now be initialized with a slice of valid response
    codes.  If none is provided or specified, the default behavior is to
    assume only a 200 response to be valid.