New version of pandoc does not understand HTML tables

[danielfernandez]

Apparently, the new version of pandoc being used (1.13.2) does not allow tables to be directly specified in HTML, like:

<table>
  <tr>
    <td>`th:async`</td>
    <td>`th:autofocus`</td>
    <td>`th:autoplay`</td>
  </tr>
  <tr>
    <td>`th:checked`</td>
    <td>`th:controls`</td>
    <td>`th:declare`</td>
  </tr>
  ...

Instead, we should use one of the available syntax extensions for tables (see http://johnmacfarlane.net/pandoc/demo/example9/pandocs-markdown.html ).

The one which renders most similarly to the old syntax is pipe_tables:

|-------------------+-------------------+-------------------|
|`th:async`         |`th:autofocus`     |`th:autoplay`      |
|`th:checked`       |`th:controls`      |`th:declare`       |
...