specify entry_points for drivers

[scottyhq]

import intake for current versions gives a FutureWarning:

/srv/conda/envs/notebook/lib/python3.7/site-packages/intake/source/discovery.py:136: FutureWarning: The drivers ['geojson', 'postgis', 'shapefile', 'spatialite'] do not specify entry_points and were only discovered via a package scan. This may break in a future release of intake. The packages should be updated.
FutureWarning)

intake                    0.5.3                      py_0    conda-forge
intake-geopandas          0.2.2                    pypi_0    pypi

It might also be convenient to have source.container() return geodataframe instead of dataframe

[ian-r-rose]

Sorry @scottyhq, I missed this. The entrypoints issue should be fixed in master, this just needs a conda/pypi release.

Regarding the container type, I would defer to @martindurant as to which is more idiomatic.

[martindurant]

If you want to have a geodataframe container, then you would need to implement such a container in intake.container.container_map, or reading from an Intake server would not work.

[ian-r-rose]

There is currently some discussion over in the GeoPandas repo as to whether to continue implementing as a subclass or with an pandas extension array, so I'd probably wait on implementing new container types here until that settles down.

Does this driver work with the Intake server as-is? I have not tried it.

BTW @scottyhq I've just published a patch release with the entrypoints specification, so that warning should be fixed now.