Reworded a few things for consistency- should fix issue #13

I also added an `usage.js` example to make sure the code kept working - this undoubtedly belongs to functional tests, but let's have it here for now. README.md has also been updated to reflect the new options and also enumerate them (which would fix issue #9)

r? @tofumatt 
Seems like all your `if`s here need a space after them :wink: