[PATCH 4 of 5] manifestv2: add support for reading new manifest format

[Mike Hommey]

On Wed, Apr 01, 2015 at 09:24:47PM -0700, Gregory Szorc wrote:
> We can force people use a modern Mercurial if there is a compelling reason
> to do so. It's annoying to force people to upgrade, sure. But if it's all
> performance and feature wins, I don't think many will complain. We've done
> this before in January 2013 by requiring Python 2.7 to build Firefox. We
> can do it again if there are good reasons.

In January 2013, python 2.7 had been released for 2.5 years. Requiring
the very last version of Mercurial is another dimension.

Mike