RFR(m): updated: JEP 269 initial API and skeleton implementation (JDK-8139232)

[Stuart Marks]

Hi all,

Thanks for the previous round of review comments. Here's an updated API and 
implementation for review.

I've run specdiff with the --hu ("hide unchanged") option, so only the bits of 
the specification that have changed are shown. As before, though, please ignore 
the spurious change to EnumSet caused by a javadoc bug.

API changes:
  - add clarifying notes on immutability
  - remove wording that implied creation of new objects
  - add "value-based" disclaimers
  - add ordering specification for List and non-ordering disclaimers
    for Set and Map
  - clarify that Map.ofEntries() doesn't store the Map.Entry objects, instead
    it extracts keys and values
  - Map.Entry instances returned from Map.entry() are *not* serializable

Other:
  - markup cleanups
  - small implementation cleanups

JEP:

     http://openjdk.java.net/jeps/269

API spec (basically List, Map, and Set):

     http://cr.openjdk.java.net/~smarks/reviews/jep269/api.20151201/

Specdiff:

 
http://cr.openjdk.java.net/~smarks/reviews/jep269/specdiff.20151201/overview-summary.html

Webrev:

     http://cr.openjdk.java.net/~smarks/reviews/jep269/webrev.20151201/

Thanks,

s'marks