osm2csv Files

Execution:
- execute in command line with filepath and key parameter, e.g.
	> java -jar harvester.jar map.osm amenity
  to get all amenities as a csv (in this case map.osm.csv).

Result:
- csv with columns x, y, cat (for lon, lat and value of given key)
- nodes with corresponding key are returned as such
- ways with corresponding key are averaged with centroid function

Remarks:
- centroid function by Robert Sedgewick and Kevin Wayne, University of Princeton