Merge upstream

First Zhihu fork version

Bump Conduit client version number

Summary: Should have been part of D3934.

Test Plan:
  $ arc diff

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4076

Conduit Protocol 5

Conduit Protocol 4