Garbled options expiries

[aisthesis]

pandas_datareader is providing nonsensical expiries due to a parsing issue. Cf. pydata/pandas-datareader#193.

The best approach may be just to create the DataFrame from scratch and work toward eliminating the dependency on pandas-datareader. This issue make options retrieval completely useless.

[aisthesis]

For any users having this issue, the temporary fix is to set the version of python-dateutil to 2.4.2 in your virtual environment. Upgrading to 2.5.2 gives you the garbled interpretation.

Since it's a problem with our dependencies and not with us, I'm not planning on doing a code fix here but will also keep the issue open.

It might be desirable here to include an integration test verifying that all expiries shown are after the current date.