Log Message:
Update to 1.6:

  - IMPORTANT: Removed support for listening on ports under < 1024
  - Support embedded NULLs in email data.
  - Fix problems with not listening properly when in daemon mode
  - Fix warnings when compiled with gcc 4.0
  - Handle empty addresses properly in logs.
  - Don't let exchange send it's strange binary data through the proxy
  - More Solaris fixes :(
  - Don't reject emails when server is overloaded or errors.
  - Don't reject emails when starting the filter command fails.