Add support for the new format used by chromeHangs.

At first look it seemed that since this script just forwards to the
symbolication server it should not care about the format change.

Unfortunately I missed two things:
* The new symbolication protocol takes a version number.
* The script does some sanity checks, so it does need to know
a bit about the new format.

BTW, where can I find some data files to test this?