Fix filter routes feature when showing arrival times

* Is shown as part of the header, so its visible when the sliding panel is collapsed.  This will allow us to filter the route lines shown on the map as well (future impl)
* Edit stop name feature still works as originally designed
* Pulls some of the default dimensions into the dimens.xml resource file.  ArrivalsListHeader retrieves and caches these values, which are used when resizing the view at runtime.