[Pool] Toward version 2.12.0 and 3.0

[Gary Gregory]

Hi all,

This is a switch from the 2.12.0 vote mail thread in order to discuss 3.0
and 2.x releases.

I propose we switch master to 3.0 and create a branch called 2.x based and
an old commit and release 2.12.0 from there.

Gary