anchor.diff:  ====== Reduce windowhandler.html flickering
   
   Per default we only overwrite the onclick events of all links on the current page to make a 'screenshot' between requests.
  -We also provide a mechanism to store the 'screenshot' on ajax requests (e.g. Post-Redirect-Get via p:remoteCommand or other components) or on every button onclick:
  +We also provide a mechanism to store the 'screenshot' on every button onclick:
   
   [source,java]
   ----------------------------------------------------------------------------
   @Specializes
   public class MyClientWindowConfig extends DefaultClientWindowConfig
  -{
  -    @Override
  -    public boolean isClientWindowStoreWindowTreeEnabledOnAjaxRequest()
  -    {
  -        return true;
  -    }
  -    
  +{    
       @Override
       public boolean isClientWindowStoreWindowTreeEnabledOnButtonClick()
       {
  
positive.code:     {
          return false;
      }
      
      @Override
      public boolean isClientWindowStoreWindowTreeEnabledOnAjaxRequest()
      {
          return false;
      }
      
      @Override
      public boolean isClientWindowStoreWindowTreeEnabledOnButtonClick()
      {
  
negative.code: also got rid of this flickering by storing away a 'screenshot' of the
  first page in onclick() and immediately restore this 'screenshot' on the
  intermediate windowhandler.html page. Technically we do this by storing
  away the HTML DOM tree and css information into the html5 localStorage and restore them on the
  intermediate page. We also introduced a WindowConfig which is able to
  parse a request and decide upon the UserAgent or any other information
  if a client will get an intermediate page or if he gets the result page
  