title: Symfony2, Twig: Better use block or variable?
body: <p>What solution is better and recommended for short string elements? To define block and let user override it contents like:</p>
  
  <pre><code>&lt;title&gt;{% block title %}{% endblock %}&lt;/title&gt;
  </code></pre>
  
  <p>or make block of variables, set their default values and let user import this block reset variable he want like:</p>
  
  <p><strong>base template:</strong></p>
  
  <pre><code>{% block variables %}
      {% set meta.title = '' %}
  {% endblock %}
  &lt;title&gt;{{ meta.title }}&lt;/title&gt;
  </code></pre>
  
  <p><strong>user template:</strong></p>
  
  <pre><code>{% block variables %}
      {{ parent() }}
      {% set meta.title = 'some title' %}
  {% endblock %}
  </code></pre>