Add query_raw method.
Fix bad resolver host name, change an error to an ArgumentError.
Added test_return_error_is_default().
Added 'default' clarification.
Changed test strategy for TestRawQuery.
Replaced TestRawQuery tests with tests that effectively stub send_plain_message instead of doing real DNS requests over the network.
Use CustomError now to more reliably determine that the error is the expected one.
Merge pull request #49 from keithrbennett/query_raw

Add query_raw method to resolver.