Fix for embedded tweet support:

Fix for embedded tweet support:

Problem:
 * Overly long embedded tweets cause Acrobat to go over the server's
  line length limit which causes the message to be silently discarded
  because of a lack of error handling in automsg.

Solutions:
 * Make each tweet in an embedded tweet chain a seperate message
   - this requires getTweet to now return a list
 * Did not fix automsg at all

Signed-off-by: Matthew Vernon <matthewv@chiark.greenend.org.uk>