views: make menu_json returns JSONP data

bijoe/views.py

@@ -187,7 +187,13 @@ class MenuJSONView(AuthorizationMixin, View):
                 'url': request.build_absolute_uri(reverse('homepage')),
             }
         ]
-        response.write(json.dumps(menu))
+        json_str = json.dumps(menu)
+        for variable in ('jsonpCallback', 'callback'):
+            if variable in request.GET:
+                response = HttpResponse(content_type='application/javascript')
+                json_str = '%s(%s);' % (request.GET[variable], json_str)
+                break
+        response.write(json_str)
         return response