let's not use lodash

This replaces the 140kb or so lodash with only the shims we use. Which is very, very few. It cuts down the dev version to about 275kb, and the minified version to 107kb. It's an insane amount of win.
We could test, but I'm going to be honest: `filter`, `map`, `forEach`, `every` and `some` were all introduced in JavaScript 1.6/ECMAScript 5.1, so if it supports forEach and map, which I'm pretty sure the code already relies on, it'll support filter.