Roll gwt to 2.7.0 (from 2.5.1)

src/DomDistiller.gwt.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!--
  Copyright 2014 The Chromium Authors. All rights reserved.
  Use of this source code is governed by a BSD-style license that can be
  found in the LICENSE file.
 -->
 <!DOCTYPE module PUBLIC "-//Google Inc.//DTD Google Web Toolkit 2.5.1//EN"
   "http://google-web-toolkit.googlecode.com/svn/tags/2.5.1/distro-source/core/src/gwt-module.dtd">
 <module rename-to='domdistiller'>
   <!-- Inherit the core Web Toolkit stuff.                        -->
+  <inherits name='com.google.gwt.core.Core'/>
   <inherits name='com.google.gwt.user.User'/>
   <inherits name='com.google.gwt.json.JSON'/>
   <inherits name='Proto'/>
 
-  <inherits name='org.timepedia.exporter.Exporter'/>
-  <set-property name='export' value='yes'/>
-
   <set-property name='gwt.logging.enabled' value='TRUE'/>
 
   <set-property name='user.agent' value='safari'/>
 
   <entry-point class='com.dom_distiller.client.DomDistillerEntry'/>
 
   <!-- Specify the paths for translatable code                    -->
   <source path='com/dom_distiller/client'/>
   <source path='de'/>
 
+  <!-- Use the SingleScriptLinker. -->
+  <add-linker name='sso'/>
+
   <!-- This provides simple implementations of java platform features used by boilerpipe but not
   available in a gwt project -->
   <super-source path='fake_java_platform'/>
 
 </module>