Update .arclint in Phabricator for phutil-library lint

Summary:
Also fix a few other minor issues:

• Use lint config.
• Fix a method signature from arc unit --everything (unrelated).
• Add a javelin doc.

Test Plan: Ran arc lint, arc unit, arc linters.

Reviewers: btrahan, joshuaspence

Reviewed By: joshuaspence

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D9072