Migrate from ledermann/rails-settings to rails-settings-cached which allows global settings

with YAML-defined defaults. Add admin page for editing global settings. Add "site_description"
setting that would show as a paragraph on the frontpage

app/assets/javascripts/application_public.js

@@ -1,3 +1,8 @@
 //= require jquery
 //= require jquery_ujs
 //= require extras
+//= require best_in_place
+
+$(function () {
+  $(".best_in_place").best_in_place();
+});