class SplittableRandom

[Doug Lea]

[Also posted on concurrency-interest.]

Thanks to all those sending quick feedback, both on and off lists!
We're increasingly confident about the value of adding
SplittableRandom, so will proceed with integration request. I'm sure
that we'll introduce incremental improvements during OpenJDK8 bake-in
phase, and apply some of the lessons learned to other code. But we
wanted to ensure that this is at least considered for inclusion along
with last of the other jsr166-related updates (that are all currently
in-process).

Paul Sandoz will follow up on core-libs-dev with the CR details, on
his way out to a well-deserved vacation. So I may request help from
others for any Oracle process issues that might arise.  The CR is far
from the end of this process, so I also plan to post follow-ups as it
progresses.

-Doug