r8104: - added support for our client library to not negotiate nt status codes, contr...

r8104: - added support for our client library to not negotiate nt status codes, controlled
  with 'nt status support' option.

- make nt_errstr() display nice strings for dos status codes encoded
  using NT_STATUS_DOS()

- no longer map between dos and nt status codes in the client library,
  instead return using NT_STATUS_DOS()

- fixed the RAW-CONTEXT test to look for
  NT_STATUS_DOS(ERRSRV, ERRbaduid) instead of NT_STATUS_INVALID_HANDLE
(This used to be commit ff5549e87ffae9f062394f30d8fd1ae95b614735)