Added tests for pages via Mink

This tests the whole library and pages without mocking via Mink and the Selenium Driver.
Just now only basic but we can improve them and add more later.
That looks interesting.

What about testing that `->click` really is sent to current collection element and not all of them. You're actually doing that in this test version for `HtmlElements`, but using dedicated methods to check radio buttons. Here `click` will be used instead of `selectRadioButtonByValue` and other fancy methods.