py3 compatible README.rst parsing
py3 compatible README.rst parsing

Hit error "UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in
position 780: ordinal not in range(128)" on py3.

googleapis/python-bigquery-sqlalchemy,mxmzdlv/pybigquery,googleapis/python-bigquery-sqlalchemy,mxmzdlv/pybigquery