title: Saving dataframe to shapefile using geopandas in python raises ValueError for bool
body: <p>When I am saving the dataframe as a shapefile with geometry I am getting the following error.</p>
  
  <pre><code>geometry  = [Point(xy) for xy in zip(df.longitude, df.latitude)]
  dfout = geopandas.GeoDataFrame(df,  geometry=geometry)    
  dfout.to_file(outputpath, driver='ESRI Shapefile')
  
  Traceback (most recent call last):
    File "test.py", line 230, in &lt;module&gt;
      main()
    File "test.py", line 223, in main
      createSHP(df,outputpath)
    File "test.py", line 150, in createSHP
      dfout.to_file(outputpath, driver='ESRI Shapefile')
    File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/geopandas/geodataframe.py", line 343, in to_file
      to_file(self, filename, driver, schema, **kwargs)
    File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/geopandas/io/file.py", line 61, in to_file
      schema=schema, **kwargs) as c:
    File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/fiona/__init__.py", line 178, in open
      enabled_drivers=enabled_drivers, crs_wkt=crs_wkt)
    File "/home/ubuntu/anaconda2/lib/python2.7/site-packages/fiona/collection.py", line 155, in __init__
      self.session.start(self, **kwargs)
    File "fiona/ogrext.pyx", line 961, in fiona.ogrext.WritingSession.start (fiona/ogrext.c:16015)
  ValueError: 'bool' is not in list
  </code></pre>
  
  <p>I havn't been able to find out what this error means.</p>