R1:0776b5ca2c4d

Update D3 to the current version

Summary:
Ref T13279. Old D3 seems perfectly fine, but most of the good references seem to have been written by people who update D3 more than once every 10 years (???).

This requires some minor API changes, see next diff.

Test Plan: See next diff.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13279

Differential Revision: https://secure.phabricator.com/D20497