Many improvements

This PR adds some really interesting improvements. We now have a configuration file for the application. We have bounding boxes AND EX_GeographicBoundingBox. We're almost compatible with WMS 1.3.0. That's wonderful.

I've improved the way we display namespaces. This is a workaround for a QGIS bug that expects href to be defined xlink:href, not nsX:href, in the getCapabilities response. Tested with the QGIS master branch, that seems to be working now. It was a bug on their side, but we wanted to improve our XML anyway, so...

Note that our client (in OrbisGIS) does not behave better regarding to namespaces. We'll have to improve that too...

Ticket on the QGIS tracker : http://hub.qgis.org/issues/7650