Upgrade to Doxia 1.1.1

We're using some old alpha version of Doxia. This will allow to use Doxia Parsers and Renderers.

Parsers we could use:

• TWiki (we already have a basic implementation, needs to be tested)
• APT

Renderers we could use:

• DocBook
• LaTex (if it's better than the wikimodel one which is very basic right now)
• RTF/FO if they're any good