Implement Split View Menus

Split View Menus:

* Remove temporary menu items
* Add Split view icon w/tooltip
* Change Split view icon state based on split view scheme
* Create permanent menu
* Localize menu strings
* Fix gear menu so it's always at top of sidebar, add tooltip

cc @JeffryBooher 

This started out in DefaultMenus.js as something like 

```javascript
$("#working-set-option-btn).on("click", funtion (e) {
       workingset_configuration_menu.open(e);
});
```

I wonder if it can be moved back there along with the splitview menu below.  Then all of this menu management goes away from SidebarView.js (if you move the working set context menu back to WorkingSetView.