Loose-ends wrapup

[Brian Goetz]

The majority of the lambda libraries code has been put back to the jdk8 
repositories.  I'm gathering a list of loose ends that we might want to 
circle back to.  The bar for nontrivial new features at this point is 
high, but there are plenty of things in the "small tweaks" category that 
we can do.

There's also lots of work remaining in improving the implementation and 
especially the documentation and specification.  This is a really great 
time to contribute improvements in this area.

Streams -- lingering feature ideas

  - Additional tweaking on range generators (see Paul's emails)
  - Convenience ints() and longs() generator methods?  (ditto)
  - Collector for frequency counting?
  - Support for state-based cancelation (e.g., cancelWhen(BooleanSupplier))
  - Support for content-based limiting (takeWhile, skipUntil)
  - Convenience methods like toList() on Stream

SAMs
  - Additional static or default methods on standard SAMs?

Point lambdafications
  - Gotta be more of these?

Helper classes
  - (I hesitate to even suggest): Optional.{filter,map,flatMap}
    Now that Stream.flatMap is settled, it becomes reasonable to 
consider these.

What others have I missed?