title: Set HTML title when using iron-router
body: <p>How to best set the HTML title when using iron-router? Here's what I'd like to do:</p>
  
  <pre><code>&lt;template name="layout"&gt;
      &lt;head&gt;&lt;title&gt;{{KAZOOM}}&lt;/title&gt;&lt;/head&gt;
      &lt;body&gt;
          {{&gt; menu}}
          {{yield}}
      &lt;/body&gt;
  &lt;/template&gt;
  
  &lt;template name="example"&gt;
      {{KAZOOM 'example page'}}
      That's just an example page
  &lt;/template&gt;
  
  &lt;template name="foo"&gt;
      {{KAZOOM 'foo page'}}
      Another example page with different HTML title
  &lt;/template&gt;
  </code></pre>
  
  <p>You see how the KAZOOM travels back in time to set the HTML title? The reason I wish to do it that way is that I consider the HTML title to be part of the content. It would be nice I could adjust the HTML title of a page by just editing the template that generated it. Unfortunately I don't see a clean way to achieve this. The closest I can think of would be named yields, then the title would be set by the route, not by the template.</p>
  
  <p>The other possibility is to just forgo the layout template and always include a header:</p>
  
  <pre><code>&lt;template name="head"&gt;
      &lt;head&gt;&lt;title&gt;{{this}}&lt;/title&gt;&lt;/head&gt;
      {{&gt; menu}}
  &lt;/template&gt;
  
  &lt;template name="example"&gt;
      {{&gt; head 'example page'}}
      That's just an example page
  &lt;/template&gt;
  
  &lt;template name="foo"&gt;
      {{&gt; head 'foo page'}}
      Another example page with different HTML title
  &lt;/template&gt;
  </code></pre>
  
  <p>That is not very nice. Do you have a proper solution to this?</p>