Revert "avoid duplicate conversions registrations"

This reverts commit 6256787.

Author: artemp

src/mapnik_datasource.cpp

@@ -195,6 +195,7 @@ void export_datasource()
              "These vary depending on the type of data source.")
         .def(self == self)
         ;
+    register_ptr_to_python<std::shared_ptr<datasource> >();
 
     def("CreateDatasource",&create_datasource);
 

src/mapnik_feature.cpp

@@ -230,4 +230,5 @@ void export_feature()
         .def("from_geojson",from_geojson_impl)
         .staticmethod("from_geojson")
         ;
+    register_ptr_to_python<std::shared_ptr<mapnik::feature_impl> >();
 }

src/mapnik_featureset.cpp

@@ -63,4 +63,5 @@ void export_featureset()
         // Python2 support
         .def("next", next)
         ;
+    register_ptr_to_python<std::shared_ptr<mapnik::Featureset> >();
 }

src/mapnik_geometry.cpp

@@ -282,4 +282,5 @@ void export_geometry()
         //.def("to_svg",&to_svg)
         // TODO add other geometry_type methods
         ;
+    register_ptr_to_python<std::shared_ptr<geometry<double>> >();
 }

src/mapnik_image.cpp

@@ -467,5 +467,6 @@ void export_image()
         .staticmethod("from_cairo")
 #endif
         ;
+    register_ptr_to_python<std::shared_ptr<image_any> >();
 
 }