Changes based on most current PR review.

https://github.com/yahoo/mojito/pull/1101
- update api docs
- linted
- updated middleware initialization to be at runtime instead based on feedback from PR
Updated api doc.
- Using app.mojito.store (as opposed to app.get('mojito.store))
- Simplify the exported function for lib/mojito.js
- linted
- merged the constructor and `createMojito` method in a single call
- updated `app.js` examples to use the revised middleware() api