403 on multiples CSS files

[h3xstream]

Multiples CSS files hosted on Google CDN servers are no longer available. The issue was already reported here:
googlecodelabs/tools#796

There is a workaround suggest here : googlecodelabs/tools#796 (comment)

[obilodeau]

I don't have time to look at this now, I'm attending an event, but I would happily merge a PR.

[obilodeau]

Fixed with #6