Fix admin form checkboxes under Firefox.

Firefox needed to detect this under the "change" event rather than the
"click" event (the click event was happening too early).

This would be a good reason to get some Selenium tests running so we
could run our test suite across real browsers, rather than just
webkit via phantomjs.

app/assets/javascripts/admin/views/checkbox_list_view.js

@@ -5,7 +5,7 @@ Admin.CheckboxListItemView = Ember.Checkbox.extend({
     return _.contains(checkedValues, value);
   }.property('content', 'checkedValues.@each'),
 
-  click: function() {
+  change: function() {
     var checkedValues = this.get('checkedValues') || [];
     var value = this.get('content.id');