bump showdown

bower.json

@@ -15,7 +15,7 @@
     "jquery-ui": ">=1.9.2",
     "bootstrap2.3.2": "^2.3.2",
     "codemirror": "^4.7.0",
-    "showdown": "^0.3.1",
+    "showdown": "^0.5.0",
     "require-css": "^0.1.2"
   }
 }