I forgot that the datasets code was not yet hooked into automatic docs generation. New datasets were not being added to the docs. This adds dataset doc generation and cleans up the docstrings to use literal blocks since over half the datasets were not be correctly rendered in the HTML docs.
DOC: Add docs for Nile dataset.
DOC: Remove generated docs from version control
DOC: Use literal block for NOTE section
DOC: Use literal block for all NOTE sections
MAINT: Allow dataset docs to be automatically generated
Coverage remained the same when pulling 8184c99 on jseabold:dataset-cleanup into a42463d on statsmodels:master.