Fixes #83

This is fantastic-- sheer feels all grown up now!

This is awesome @willbarton A few stylistic comments, none of which I think should hold up this being merged if it doesn't make sense to tackle them now:

• It would be good to eventually better align this with https://github.com/cfpb/open-source-project-template, specifically:
  • Adding the how to test the software section. nose and mock are mentioned for testing, but those are never touched on again in the Readme.
  • Change COPYING.txt filename to LICENSE, as it is referenced in the Readme.
• The bulleted lists use a mix of styles, for example, the list under general usage includes lines that end in a period and lines that don't, and this line is capitalized after the colon, while the others aren't (I prefer caps myself). Also, Elasticsearch is downcased in this list while it is capitalized elsewhere.

I think Ans's first bullet is worth addressing before merge.

• Testing instructions definitely need to go in there.
• The license link at the end of the README is correctly linked to COPYING.txt, but it would be nice to use the new standard name.

@anselmbradford Ok, I've taken care of both those points in 1f17392 and d7ffca4. Testing should absolutely be in there, and that's an oversight on my part.

The bulleted lists... I copied them straight from the output of sheer -h (and sheer index -h, etc). So I've updated the sheer command itself and what it outputs with -h as well as the README.

All good with me, now! 👍 @rosskarchner, ready for mergifcation?

Roll that beautiful bean footage.