Corrected 'character' leaking into global scope.

My test suite for Behaviour Assertion Sheets caught a couple instances of the `character` variable leaking into global scope, due to missing declarations at the top of their respective functions.

I've corrected this issue, and fixed an additional typo I found in CSSTree.js. (`chracter`)

If you decide to merge, it'd be awesome if you pushed an npm update too! :)

(Thanks again for CSSTree, it's helped me enormously!)