URLs in package.json are wrong

Hi!

While trying to find a JS lib for fixtures, I stumbled about js-fixtures and noticed that the URLs you use for your project in your package.json aren't correct, see: https://npmjs.org/package/js-fixtures
This commit should fix that. :)

It was:
https://github.com/badunk/fixtures

It should be:
https://github.com/badunk/js-fixtures