retry_with_logging(), retry_and_report_killed() take optional retry_classes + fail_classes arguments;
it doesn't make sense for retry() to do so otherwise.

Summary: As above.

Test Plan: Test added in tests/general/test_logging.py

Reviewers: emfree

Differential Revision: https://review.inboxapp.com/D225
Support for inbox.util.eas in the /inbox-eas repo; this is where EAS-specific util code would live.

Summary: As above.

Test Plan: Sync runs as before.

Reviewers: spang

Differential Revision: https://review.inboxapp.com/D226
Fixes T120: resume 'killed' syncs on restart. Also consolidates account sync_state updates.

Summary: As above.

Test Plan: Killed, stopped syncs + restarted server.

Reviewers: emfree

Differential Revision: https://review.inboxapp.com/D227