Matt Reklaitis: Get stomp working with sbcl, plus tweak when ack gets sent.

Reviewer: sergey

- tested manually with sbcl

- Replace cl-stomp's string-to-bytes and string-from-bytes with
  babel equivalents for utf-8 support.

- Removed the unused force option to qres-stomp-client:stop to
  avoid issues with using kill-process.

- Rearranged code in handle-stomp-request so that the stomp
  transaction is started and an ack is sent as soon as the request
  is received.  Previously, the ack wasn't sent until after the
  request had been processed.