title: Output request parameter by template
body: <p>Is it correct to say that there is no simple tag that just writes some http get
  query parameter?
  If all needed is printing a http get query parameter e.g. <code>?q=w</code>
  can I directly use the value q with a template tag or need the copy
  the value in the request handler?
  Is it possible to more directly pass values (all values) from http get
  to template?
  Because copying every value seems repeating the same handling many
  times</p>
  
  <pre><code>template_values = {'q':self.request.get('q'),...
  </code></pre>
  
  <p>It should be possible to iterate the parameter set. Can you recommend
  that or any other solution? </p>