Updated instructions for recent mapnik-osm versions.
Updated instructions for recent mapnik-osm versions.

Recent versions of mapnik-osm provide a generate_xml.py script to
replace the set-mapnik-env.

dittaeva/ocitysmap,maposmatic/ocitysmap,maposmatic/ocitysmap,wonderchook/OcitySMaps,ccnz/eqnz-ocitysmap,dittaeva/ocitysmap,maposmatic/ocitysmap