2.8 collections

I have finished a first implementation of 2.8 collections. I'd like to
submit this as a SIP, so that it can be discussed and improved. For
practical reasons, the current design is already intregrated in trunk.
But this should not stop it from being discussed seriously.

Personally, I will let collections rest for the next two weeks or so,
because I need all my bandwidth for the Eclipse IDE overhoal.

Thanks

 -- Martin