Update to latest WebDriver spec

WebDriver W3C Candidate Recommendation 26 September 2017

Compat Busters

For newer web drivers that implement the WebDriver W3C candidate recommendation spec

• $session->window() now returns a WebDriver\Window object for method chaining
• $element->submit(), $element->equals(), $element->displayed(), $element->location(), $element->location_in_view() and $element->size() are unsupported; refer to $element->click(), $element->property(), and $element->rect()
• $session->keys(), $session->orientation(), $session->alert_text(), $session->dismiss_text(), $session->moveto(), $session->click(), $session->buttondown(), $session->buttonup(), $session->doubleclick(), $session->execute_sql(), $session->location(), $session->browser_connection(), $session->window_handle(), $session->window_handles(), and $session->execute_async() are unsupported; refer to $session->actions(), $session->alert(), and $session->execute()

For older web drivers still using the (legacy) JSON Wire Protocol:

• use $session->legacyWindow() instead of $session->window()