4138 confirm location selection

These changes add a new option to the component called `confirmLocationSelection`. When this is set to true (defaults to false), new behaviour is defined.

* For search results, a user is automatically shows disambiguation page if required and when they select a news region, the form doesn't reset
* For search results that don't require disambiguation, the results stay open when a location is selected
* For each of the cases above, a class name of "selected" is added to the list item allowing developers to style the selection differently

There is also a `persistUserLocation` method that is a convenience method for persisting the locserv cookie.

I've also started to document the events emitted in the component. This is ongoing.

These changes should allow news to use the component in their new designs whilst maintaining existing functionality. A test option has been added to the PAL test page which is part of the BitBucket PR.

Kevin