.disconnect() should provide a callback

[chadxz]

when calling .disconnect(), you're performing a socket.end() but providing no callback for when the socket is completely closed. You could do this by listening to the 'close' event, i.e.

AsteriskAmi.prototype.disconnect = function(callback){
  this.reconnect = false;
  this.socket.on('close', function () {
    callback();
  });
  this.socket.end(this.generateSocketData({Action: 'Logoff'}));
}

You shouldn't need to remove the close listener on the socket because the socket should be destroyed when the connection is closed.

Sorry I'm lazy and didn't do a PR because this was just a tangential thought while reviewing someone's code.

[chadxz]

I see now that you expose an "ami_socket_close" event when the underlying socket is closed, so I suppose a consumer of this library could use that, i.e.

function closeAmi(callback) {
  ami.on('ami_socket_close', function () {
    callback();
  });
  ami.disconnect();
}