Remove grunt dependency

Addresses #25.

This also removes the confusing duplicate of `src/ractive-adaptors-backbone.js` and `/ractive-adaptors-backbone.js` -- some people send PRs to one but not the other.

* Removes all grunt-related things. The only functions grunt fulfilled was (1) jshint, and (2) uglifyjs compression.
* Implement jshint checking via `npm test`.
* Implement uglifyjs compression via `npm run prepublish`.
* Removes `src/`.