Bump codemirror.

Fixes selections not showing in chrome / brave.

bower.json

@@ -22,7 +22,7 @@
     "amber-contrib-web": ">=0.5.0",
     "jquery-ui": ">=1.9.2",
     "bootstrap": "^3.3.4",
-    "codemirror": "^5.10.0",
+    "codemirror": "^5.25.2",
     "showdown": "^0.5.0",
     "require-css": "^0.1.2",
     "typeahead.js": "^0.10.5"