Reduce false positives and separate out additional link styles

Hey @nicovanzyl,

Thanks so much for creating Chameleon. Please see my changes below:

- Increase attr selector specificity to reduce false positives (See http://jsfiddle.net/adamschwartz/nb597jL0/show/light/)
- Separate out additional link styles (and add to demo)
- Make additional link files an optional include in the `install.json`
- Update README to reflect these changes

Let me know your thoughts! Thanks again.

– Adam
I'm not sure about the `//`, this would make it not match `www.500px.com`, or any other subdomain for that matter