[WIP] Some progress for cudf serialization

[rjzamora]

Certainly more work to do here, but submitting a rough PR in response to dask#2746 (comment)

[mrocklin]

I recently discovered that cudf already has some code for this here:

https://github.com/rapidsai/cudf/blob/7312d4aa413eafdad28b67efccbc3dc15d9b5e27/python/cudf/dataframe/dataframe.py#L122-L135

https://github.com/rapidsai/cudf/blob/7312d4aa413eafdad28b67efccbc3dc15d9b5e27/python/cudf/dataframe/series.py#L102-L111

I wonder if we can do this work there.

[mrocklin]

@rjzamora I'm going to try seeing how far I can get the cudf serialization code to go. You may want to hold off on work here for an hour or two

[rjzamora]

@mrocklin - Sorry, missed your last message. That is interesting about the serilize/deserialize in cudf - let me know if you do/don't want me to push on this