Periodic and timer read streams

Signed-off-by: Julien Viet <julien@julienviet.com>
DatagramSocket extends ReadStream<DatagramPacket>

Signed-off-by: Julien Viet <julien@julienviet.com>
DatagramSocket sender as a WriteStream

Signed-off-by: Julien Viet <julien@julienviet.com>
Implemented missing callback to ReadStream#endHandler when unregistering consumer

Signed-off-by: Julien Viet <julien@julienviet.com>
Setting a null handler on a message consumer should unregister the consumer + more message consume tests
Signed-off-by: Julien Viet <julien@julienviet.com>
Merge pull request #933 from vietj/master

Rxification cont