title: Creating hierarchical tables in markdown
body: <p>I want to build a complex table like this:</p>
  
  <pre><code>| some thing | more important | up here |
  |------------|----------------|---------|
  | a  |a1     | b     |d       | c       |
  |------------|----------------|---------|
  | 1  |2      | 1     |2       |         |
  </code></pre>
  
  <p>Is it possible using gf-markdown?</p>