R1:53e95d37cfb7

Calendar - make calendar publicly accessible

Summary: yay public policy. Ref T4830.

Test Plan: browsed about calendar from a logged out browser

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T4830

Differential Revision: https://secure.phabricator.com/D9120