minor cleanups (#225)

* use normal html self-closing tags

* stop using obsolete test integration

* make test more straightforward

* removed unused setting

admin_interface/static/admin_interface/magnific-popup/jquery.magnific-popup.js

@@ -1808,7 +1808,7 @@
                 _mfpTrigger('LazyLoad', item);
 
                 if(item.type === 'image') {
-                    item.img = $('<img class="mfp-img" />').on('load.mfploader', function() {
+                    item.img = $('<img class="mfp-img">').on('load.mfploader', function() {
                         item.hasSize = true;
                     }).on('error.mfploader', function() {
                         item.hasSize = true;
@@ -1864,4 +1864,4 @@
 
     /*>>retina*/
     _checkInstance();
-}));
+}));