enforced explicit specification of option start-db because it's way to complicat
ed; removed nonsense default value empty list of osm_files for osm_postgis_trans
form.py; clearing data-dir if exception occurs (e.g. port is occupied) and warni
ng if directory isn't empty initially (in order to allow purging the directory w
ithout further notice); changed pg_version to tuple rather than string in osm_po
stgis_transform.py; validation of data_dir added (should fail if is a file); reo
rdered imports; switched to plac; changed to skip_start_db parameter; documented
 all options; added logging messages for difference between creating and using d
ata directory;\n\nosm_postgis_transform_prequisites.py: fixed linuxmint installa
tion; switched from print to logging