Make Asset Pipeline compatible with Chrome DevTools Autosave

https://github.com/NV/chrome-devtools-autosave doesnt play nice with
Asset
Pipeline. https://github.com/NV/chrome-devtools-autosave/issues/27

The culprit of the problem is in the assets URLs. I cannot decipher a
file
path by its URL. For instance, /assets/main.css?body=1 could be either
app/assets/stylesheets/main.css, lib/assets/stylesheets/main.css
or vendor/stylesheets/main.css.

To fix it, we could either make URLs match their file path:
/app/assets/stylesheets/main.css?body=1

or introduce source-path query parameter:
/assets/main.css?body=1&source-path=app/assets/stylesheets/main.css

Any help would be good.