title: avoid global redraw on modular view model
body: <p>how would I be able to avoid a global redraw = call to the main view function 
  while changing the view of a submodule like in the main Module view method:</p>
  
  <pre><code>m("body", [
             m("#head", {...}),
             Menu.show(this),
             Footer.show(this)
  ])
  </code></pre>
  
  <p>where the static show method looks like :</p>
  
  <pre><code>    function show(app)
      {
          if (inst == null)
              inst = new Footer(app);
          return inst.view(app);
      }
  </code></pre>
  
  <p>Now it should increase the already nice performance if there is a way to run the view method of 
  a sub view without running the main view method in case the changes in the sub view have only
  local effects. Does this make sense?</p>
  
  <p>Axel</p>