TL19 release build tonight

[Karl Berry]

FYI, I hope that tonight will be the final build for the TL'19 release.

I've reverted pgf to its previous version (I hope).

I took today's updates from CTAN, but don't plan to take any more until
after the release is made.

Please consider the repository frozen as of now.  If anyone feels the
need to commit emergency fixes or anything else, please write me first
to avoid surprises.

Thanks,
Karl