Support formatting of tabular data

[corvus-ch]

I would like to be able to format text as table.

Example:

|_. Title A |_. Title B |
| Risus | Fermentum |
| Ligula | Quam Sollicitudin |

See also http://redcloth.org/textile/page-layout/#tables.

[marubinotto]

You can do that by writing:

||Cell 1||Cell 2||Cell 3||
||Cell 4||Cell 5||Cell 6||