#7 read xml map data

[Johannes Hanika]

rearrange the MapInformation::readMap function, so that
it parses some nice xml files. there should also be a
possibility to get positions for point lights.

we will need a second xml file type which stores meta
information like starting points, some moving objects..
(concerning the game, not the voxel tree)

[Christian Himpel]

Logged In: YES
user_id=894303

parsing map files with libxml is done by now. i will take
care about the other two requests, prepare for the
possibility to get positions for point lights and the meta
information xml file, in a couple of weeks or so.