FEATURE: more than 1 site customization can be enabled at once

FIX: more robust site customizations

Rewrote site customization to use distributed cache and a much cleaner
css delivery mechanism

app/controllers/site_customizations_controller.rb

@@ -0,0 +1,9 @@
+class SiteCustomizationsController < ApplicationController
+  skip_before_filter :check_xhr, :redirect_to_login_if_required
+
+  def show
+    expires_in 1.year, public: true
+    render text: SiteCustomization.stylesheet_contents(params[:key], params[:target] == "mobile" ? :mobile : :desktop),
+           content_type: "text/css"
+  end
+end