Can you add a comment to the effect of:
Enrichment pattern to make the C(ompressed)BitSet look more like a scala bit set?

Also, can you add a TODO to just make a wrapper of CBitSet as a scala.collection.SortedSet[Int]? With that, we wouldn't need the enrichments.

http://www.scala-lang.org/api/2.9.2/index.html#scala.collection.SortedSetLike