DOC: pin ipython version to avoid bug with savefig
DOC: pin ipython version to avoid bug with savefig

See https://github.com/ipython/ipython/issues/8733#issuecomment-208544701 for more details

geopandas/geopandas,geopandas/geopandas,jorisvandenbossche/geopandas,micahcochran/geopandas,IamJeffG/geopandas,geopandas/geopandas,ozak/geopandas,jdmcbr/geopandas,jorisvandenbossche/geopandas,jorisvandenbossche/geopandas,micahcochran/geopandas,ozak/geopandas,jdmcbr/geopandas