[development] Taxonomy2

[Jeff Eaton]

I have to confess that I've been following Category's development, and
while I can attest to the developer's dedication, I don't think it's a
good idea. At its core, it's a hack that merges book and taxonomy
functionality without re-assessing the underling architecture. It makes
sense as a contrib module for sites that really need it, but I think
moving core in that direction would be a mistake.

Far better, IMO, to explore a more robust relationships system that
*encompasses* taxonomy-style metadata and book-style relationships (as
well as other stuff). There are a couple of projects along these lines
already. If there's talk of revisiting something as fundamental as
taxonomy, make the project worth the effort.

--Jeff