Patch Mithril with a bidi attribute

Enables quick bidirectional bindings. So instead of this:

<input value={prop()} oninput={m.withAttr('value', prop)}/>

... we can do this:

<input bidi={prop}/>

framework/core/js/admin/Gulpfile.js

@@ -10,6 +10,7 @@ gulp({
     bowerDir + '/es6-micro-loader/dist/system-polyfill.js',
 
     bowerDir + '/mithril/mithril.js',
+    bowerDir + '/m.attrs.bidi/bidi.js',
     bowerDir + '/jquery/dist/jquery.js',
     bowerDir + '/moment/moment.js',