Docs fixes

[willkg]

This does some minor docs cleanup.

It also creates an ESTestCase, cleans up the tests and adds ESTestCase documentation to the docs.

r?

[willkg]

@robhudson Can you take a look at this in the next couple of days?

[robhudson]

Good stuff. I commented on all I could find.

[willkg]

Thank you soooo much for looking at that.

I fixed the issues you mentioned (except the DECAPITATED one ;) ), rebased and landed it:

• 9806e6d Update CHANGELOG
• 69e99df Add elasticutils.estestcase.ESTestCase
• 5801280 Clean up, correct and reduce documentation