Download cities database.

def download():
    """Download cities database."""
    url = "http://download.geonames.org/export/dump/cities1000.zip"
    logging.info("Download cities from %s", url)

    if not os.path.exists(MISC_PATH):
        os.makedirs(MISC_PATH)
    zip_path = os.path.join(MISC_PATH, "cities1000.zip")
    urlretrieve(url, zip_path)
    with zipfile.ZipFile(zip_path, "r") as z:
        z.extractall(MISC_PATH)