Hey Guys!

I'm sorry for the missing update - I'm a bit restricted in time for private projects.
The Branch is still there and the featureset is pretty much:
* CacheController Service to manage Cache-Control headers
* Cachebusting
  - HTML and CSS Rewrite + manage of CC header
* Way more unit tests
* Some refactorings

The branch is available here: https://github.com/iwalz/AssetManager/tree/static-references
Cachebusting works fine,  but some of the Classes (like CacheController) are not yet complete.

I started to focus on another technology for Cachebusting (an apache module: https://github.com/cachebusting/apache-cachebusting), so I've never finished that though. I'll try to merge this branch back and will have a look about the missing parts of the implementation. Hence it's functional, it shouldn't be much that needs to be done.