new markdown engine compatibility

assets/javascripts/image-tag-whitelist.js

@@ -1,12 +1,14 @@
-import WhiteLister from 'pretty-text/white-lister';
-
 export default {
   name: 'dropcap',
 
   initialize() {
-    const whiteLister = new WhiteLister();
-    whiteLister.whiteListFeature("dropcap", [
-      'span.dropcap'
+    setup(helper);
     ]);
   }
 };
+
+
+export function setup(helper) {
+  helper.whiteList([ 'span.dropcaps',
+                     'span.sclass'
+                   ]);