Disable asset caching for Facia tool

Ideally we should asset hash files, but this is a quick fix for an annoying situation (we deploy and the editors can't see the changes because their browser has cached the files). As it's a single page app I think this is OK.

![cat](https://cloud.githubusercontent.com/assets/1001642/4703427/faa15cf4-586a-11e4-93b4-6e5129e292b9.gif)