Encode simple features to CSV; supports only point geometries.
>>> feat = Feature(1, {"type":"Point", "coordinates":[1,1]}, {"a":"b"})
>>> c = CSV()
>>> c.encode([feat]).replace("\r\n", " ")
'id,a,geometry 1,b,"1,1" '
>>> c.encode([feat], ["geometry","a","b","id"]).replace("\r\n", " ")
'geometry,a,b,id "1,1",b,,1 '
>>> c.encode([feat], props=["geometry","id"],fixed_props=True).replace("\r\n", " ")
'geometry,id "1,1",1 '