No line delimiter

This pull request adds a fix to make the STOMP library cope with RabbitMQ, which formats its messages differently. The problems boils down to the fact that according to [the STOMP spec](http://stomp.github.com/stomp-specification-1.1.html#STOMP_Frames), a frame will be delimited by a `^@` (NUL) character, **which may be followed by any number of `\n` (EOL)s**.

Reproduce script:
```sh
$ xp -d '$conn= new \org\codehaus\stomp\StompConnection("example.com", 61613); 
  $conn->connect("user", "*****"); 
  return $conn->receive(1.0);'
NULL
```

Before this pull request, this would hang and not exit until the default 60 seconds read timeout.