Normalize code style

I went through the code and normalized some code style inconsistencies, primarily:

* `typeof Variable === 'undefined'` to `Variable === undefined`, previously when this has come up we've always settled on not using `typeof`, it's faster this way and if `undefined` is replaced, well, everything is broken anyway.
* `String == String` to `String === String`, no reason not to.
* `name in object` to `object[name] !== undefined`, not identical, but *much* faster and I've only changed the safe ones.

Feel free to object to some or all of it.