Fix NTLM related test failures.

Fix NTLM related test failures.

* Provide a more descriptive [Obsolete] message for the legacy API.

* Refuse to send the LM response unless explicitly enabled with
  Type3Message.DefaultAuthLevel.  The LM response is only actually
  checked by old, pre-historic servers and sending it exposes the
  user's password to very weak encryption.

* Fix some problems when encoding / decoding problems in Type2Message.

* Type3Message now encodes host and domain name in a case-sensitive
  way, fixes the tests.