fixing unit tests

js/common.js

@@ -16,7 +16,7 @@ global.zlib = require('./zlib-1.2.11').zlib;
 require('./prettify');
 global.prettyPrint = window.PR.prettyPrint;
 global.prettyPrintOne = window.PR.prettyPrintOne;
-global.showdown = require('./showdown-1.9.0');
+global.showdown = require('./showdown-1.9.1');
 global.DOMPurify = require('./purify-1.0.11');
 global.baseX = require('./base-x-3.0.5.1').baseX;
 require('./bootstrap-3.3.7');