Eliminiate lodash dependency

[wkirby]

We're not using lodash for anything particularly exciting. We can eliminate it as a dependency with a little work.

[wkirby]

Nevermind. Eliminating lodash actually increased our final file size, as the es6 => es5 transpilers aren't actually as efficient as the lodash source.

In practice, even just scoping our lodash requirement to the modules we use saves us 0.1kb.