Date handling

[redhog]

Broken/missing dates break parsing. To fix:

https://github.com/emerald-geomodelling/libgeosuiteprv/blob/master/libgeosuiteprv/__init__.py#L32

should change into

'date': parse_date(firstline_list[2]),

and

def parse_date(v):
    try:
        if len(v) >= 8:
            return dateutil.parser.isoparse(v).date()
    except ValueError as exception:
        logger.debug("Unable to parse date as iso %s: %s" % (v, exception))
    try:
        return dateutil.parser.parse(v, parserinfo=dateutil.parser.parserinfo(dayfirst=True)).date()
    except Exception as e:
        logger.debug("Unable to parse date %s: %s" %(v,e))
        return v

should be added (see libsgfdata for similar code)...