improved touch test + wd upgrade

@jlipps @imurchie I've changed the wd touch/multitouch api a bit so that it allows more sugar, see the test below, the element does not need to be set upfront in touch actions, it it is able to use the current elemnt context like `click`.

btw, I couldn't get the whole thing to pass, because of xpath issue, but the new wd version should be able handle it.