v2.5.0

• Feature: Add HTTP timeout option.
  (#114 by @Rakdar and @clue)

  This now respects PHP's default_socket_timeout setting (default 60s) as a
  timeout for sending the outgoing HTTP request and waiting for a successful
  response and will otherwise cancel the pending request and reject its value
  with an Exception. You can now use the timeout option to
  pass a custom timeout value in seconds like this:

  $browser = $browser->withOptions(array(
      'timeout' => 10.0
  ));
  
  $browser->get($uri)->then(function (ResponseInterface $response) {
      // response received within 10 seconds maximum
      var_dump($response->getHeaders());
  });

  Similarly, you can use a negative timeout value to not apply a timeout at
  all or use a null value to restore the default handling.

• Improve documentation for withOptions() and
  add documentation and example for HTTP CONNECT proxy.
  (#111 and #115 by @clue)

• Refactor Browser to reuse single Transaction instance internally
  which now accepts sending individual requests and their options.
  (#113 by @clue)