swift234

At long last, land the implementation of <rdar://problem/16397000> Should be able to override stored properties

This means that we now synthesize getters and setters a lot more than we used to, so the
implementation work on this shook out a ton of bugs with them.

There is still one failure that I don't understand at all (test/stdlib/NewArray.swift.gyb), 
nor do I understand how to diagnose the problem, so I XFAILed it and filed rdar://16604980 to
track fixing it.



Swift SVN r16299