minibar_offline: Update the API exported by pgf_offline.js to be compatible with pgf_online.js

This makes the minibar offline demo work again.

src/www/minibar/minibar_offline.js

@@ -0,0 +1,18 @@
+
+var offline_options = {
+  grammars_url: "/~hallgren/hs2js/test/",
+  grammar_list: ["Foods.pgf","Smart.pgf","Phrasebook.pgf"]
+}
+
+var server=pgf_offline(offline_options);
+
+var minibar_options= {
+  show_abstract: true,
+  show_trees: false,
+  show_grouped_translations: false,
+  default_source_language: "Eng",
+  try_google: true,
+  random_button: false
+}
+
+var minibar1=new Minibar(server,minibar_options);