Version 3.4.0

There were 5 changes in Retype 3.4.0.

New

1. New hub Project config with < header link, see #592
2. New toc Project and Page config and features, see #598
3. Automatically scroll ToC with page content, see #375

Improved

1. Upgrade Octicons icons library from v19.6.0 to v19.7.0

Fixed

1. Tree nav expanded state not saving