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This fixes a bunch of KnownFailures, and adds a bunch of new features. I've
updated the tests correspondingly (though doubtless we could add a lot more
tests now, if we wanted to).

I regenerated Constants.java manually, and explained how in its javadoc.

I've added the upstream VERSION file so it's easier to see what upstream
version we're at. (Constants now contains the version number too, but that's
less obvious.)

All our changes now have android-changed markers. I'll see about getting them
pushed upstream next week.

(This change best reviewed with "ignore whitespace". It looks like we made a
bunch of whitespace "corrections" when we imported this source, which just
makes it harder to stay in sync. I've taken the upstream copies of files that
only had whitespace differences.)