v0.1.1

Fixed

• preview_mail no longer describes itself as building "exactly the message send_mail
  would build". It is registered whether or not sending is switched on, so with
  SMTP_ALLOW_SEND unset it was pointing at a tool absent from the same tools/list —
  and a reader holding a reference to a tool that is not there reads the gap as a broken
  server rather than as the default it is. The description now stands on its own, says
  that the sending tools register only when SMTP_ALLOW_SEND is true, and points at
  get_server_info for whether sending is on. No behaviour changes, and the default
  stays off.