[oe] Preparing for release - Freeze on master

[Graham Gower]

 Everyone is going to want to apply fixes to the release, so it makes
sense to have this as a new stable branch.

OE is in a relatively stable state right now with no major changes
causing large fallout recently. So, why not just branch it already and
apply the same commit policy as the existing stable branch.

More importantly are the logistics of handling what fixes go onto the
both branches or only the dev branch. Since the current stable branch
has been stale since I became involved in OE, I don't really know how
this works but I am very interested in submitting fixes for a stable
branch over the next few months.

-Graham