Fixed dbox crash issues in callbacks when errors are returned from server

[jeremycondon]

The callbacks when errors are encountered attempt to parse the output on each of the verbs. Changes is as follows cb(e ? null : r.statusCode, JSON.parse(b)) cb(e ? null : r.statusCode, e ? null : JSON.parse(b))

[jeremycondon]

It may be more correct to wrap a try/catch around the JSON.parse in case the response from the server is not valid