Update script to Boostrap 3

[siamkreative]

Hi there,

This python script seems to do exactly what I'm looking for. In the past, I used CSS namespacing, but it is less reliable than prefixes.

Would you be able to update your script to Boostrap 3?

Cheers

[siamkreative]

FYI: https://gist.github.com/macanderson/6128137