There is an EPiServer Add-on for this that you can download in the Add-on store.
I can not find CMS.Sources.3.0.1097.nupkg in this link http://www.episerver.com/add-on-store/
Seem to be this add-on does not published!
You also contact me for futher information via email (email@example.com)
Ah, I saw that you get it through EPiServer Add-On channel! ;)
But anyway you should add a new line in your framework config as:
To start using the uncompressed files provided by this add-on you have to add <clientResources debug="true" /> to the episerver.framework section in EPiServerFramework.config
Thanks in advance