Fix bugs in intra-site linking

* Refactor event handling in controllers to use a method to define
  the hash (and thereby allow inheritance)
* Refactor link handling so that links which should be handled by the
  router can be handled by the base class
* Change the router to throw out controllers for pages which aren't
  on-screen (and thereby avoid a lot of weirdness)

src/scripts/controllers/item_page_controller.coffee

@@ -89,8 +89,9 @@ module.exports = class ItemPageController extends BaseController
 
     # Backbone.View Overrides ######################################################################
 
-    events:
-        'change .includeTools': 'onToolsBoxToggled'
+    events: ->
+        return _.extend super,
+            'change .includeTools': 'onToolsBoxToggled'
 
     # Private Methods ##############################################################################