Change assertIn to assert_ for python 2.6 support
Change assertIn to assert_ for python 2.6 support

jdmcbr/geopandas,jorisvandenbossche/geopandas,perrygeo/geopandas,micahcochran/geopandas,geopandas/geopandas,fonnesbeck/geopandas,ozak/geopandas,jorisvandenbossche/geopandas,geopandas/geopandas,maxalbert/geopandas,urschrei/geopandas,kwinkunks/geopandas,micahcochran/geopandas,koldunovn/geopandas,jdmcbr/geopandas,geopandas/geopandas,ozak/geopandas,scw/geopandas,snario/geopandas,IamJeffG/geopandas,jorisvandenbossche/geopandas