[WIP] New steps - verify selected, verify not selected

[chris-bingham]

• Steps to verify that an item is selected or that it is not selected
• These work for checkboxes, radiobuttons, options in a select element
• Decided to write these as I found it can be necessary to check whether a checkbox is checked without then checking it when it isn't

[juliensz]

You do not manage the time out if it does not find it as for this code:

* Verify {{element}} is not visible {
        await not$(element, undefined, VERIFY_TIMEOUT, true);
}

[vptes1]

This is already handled by the selected and not selected ElementFinder props. For example, Verify 'list item, selected' is visible (verify that a visible element that matches props 'list item' and 'selected' exists). Check out elementfinder.js.

This was a conscious design decision: anything that describes the state of html is to be described by a prop, and multiple props can be combined to form new props.

Now, if you feel there is a special need to have a more natural-sounding step just for the selected state, I'm totally open to discuss that :) Though, this too can be achieved through props, for example, with props({'selected list item': '.list-item, selected'}) and then using Verify 'selected list item' is visible.