Actually saving and loading the prefs

lib/api.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 133 matching lines @@
       return defaultMatcher.matchesAny(url, contentType, documentHost, thirdParty);
     },
 
     getElementHidingSelectors: function(domain)
     {
       return ElemHide.getSelectorsForDomain(domain, false);
     },
 
     getPref: function(pref)
     {
-      return Prefs[pref];
+      return Prefs.values[pref];
     },
 
     setPref: function(pref, value)
     {
-      Prefs[pref] = value;
+      Prefs.values[pref] = value;
+      Prefs.save();
     },
 
     forceUpdateCheck: function(eventName)
     {
       checkForUpdates(true, _triggerEvent.bind(null, eventName));
     }
   };
 })();