Load plugins/sourced JS files into the plugins namespace.

content/io.js

@@ -793,7 +793,7 @@ lookup:
                                            .getService(Components.interfaces.mozIJSSubScriptLoader);
                     try
                     {
-                        loader.loadSubScript(uri.spec, modules);
+                        loader.loadSubScript(uri.spec, plugins);
                     }
                     catch (e)
                     {

content/liberator.js

@@ -27,6 +27,7 @@ the terms of any one of the MPL, the GPL or the LGPL.
 }}} ***** END LICENSE BLOCK *****/
 
 const plugins = {};
+plugins.__proto__ = modules;
 
 const liberator = (function () //{{{
 {