v0.7.0

• Feature / BC break: Replace depreacted SocketClient with Socket v0.7 and
  use connect($uri) instead of create($host, $port)
  (#51 by @clue)

  // old
  $connector = new React\SocketClient\TcpConnector($loop);
  $client = new Client(1080, $connector);
  $client->create('google.com', 80)->then(function (Stream $conn) {
      $conn->write("…");
  });
  
  // new
  $connector = new React\Socket\TcpConnector($loop);
  $client = new Client(1080, $connector);
  $client->connect('google.com:80')->then(function (ConnectionInterface $conn) {
      $conn->write("…");
  });

• Improve test suite by adding PHPUnit to require-dev
  (#50 by @clue)