REP-819 Keystone V3 Filter

The mess that is Keystone v3! Comment on _everything_ so we can get this fixed up. =)
Why is this private to the package?  Instead the function which access the token should be made accesible.

Should probably be:

````scala
private[this] var cachedAdimnToken: String = null
````

Also you should probably use Option instead of null.