Some pullbacks

[Brian Goetz]

We would like to pull back two small features from the JSR-335 feature plan:

  - private methods in interfaces
  - "package modifier" for package-private visibility

The primary reason is resourcing; cutting some small and inessential 
features made room for deeper work on more important things like type 
inference (on which we've made some big improvements lately!)  Private 
methods are also an incomplete feature; we'd like the full set of 
visibilities, and limiting to public/private was already a compromise 
based on what we thought we could get done in the timeframe we had.  But 
it would still be a rough edge that protected/package were missing.

The second feature, while trivial (though nothing is really trivial), 
loses a lot of justification without at least a move towards the full 
set of accessibilities.  As it stands, it is pretty far afield of 
lambda, nothing else depends on it, and not doing it now does not 
preclude doing it later.  (The only remaining connection to lambda is 
accelerating the death of the phrase "default visibility" to avoid 
confusion with default methods.)