Summary:
- Add an Application.
- Move routes to the application.
- Move nav out of tabs (which no longer exist).
- Fix a couple of random things.
Test Plan: Viewed sent/received mail logs. Performed send/receive tests. Viewed email details.
Reviewers: btrahan, vrana
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T631, T1569
Differential Revision: https://secure.phabricator.com/D3255
