Work on asynchronous select widget loading.

Not working yet, but significant progress.

resources/js/select-widget-support.js

@@ -0,0 +1,14 @@
+        /**
+         * update the select menu with id `wid` from this `data` whose fields include
+         * this `entity_key` and these `fields`
+         */
+        function updateMenuOptions(wid, entity_key, fields, data){
+          $('#' + wid).children().filter(function(){
+            return $(this).attr('selected') === undefined;
+          }).remove().end();
+
+          $.each(data, function(key, entry){
+            $('#' + wid).append(
+              $('<option></option>').attr('value', key).text(entry));
+          });
+        }