[Qgis-developer] Added categories to qgis wiki

[Otto Dassau]

Hi, 

I added several categories to the qgis wiki. You reach them via the
left main menu "Categories". I also put almost all existing pages in
one or more categories. This could be extended and improved, of course,
but is a beginning and makes orientation in the wiki easier, I hope.

http://www.qgis.org/wiki/Special:Categories

Please feel free to add more useful categories, if you like.

Regards,
 Otto