Minor corrections added, documentation updated. Slowly sorting out how the .prj file parameters need to be exported. This will still take some time.

added minor corrections to functions after noticing some things in the
benchmark files ("name" attribute of gml points
can also be something else than "origin" now, point tibbles without a
"name" column are now accepted, polylines can now have more than 2
points and are still written to xml correctly)