LibreSignage v0.2.1

This is the first patch release in the LibreSignage v0.2.x
series. This release contains the following fixes:

- Fix a bug where the editor timeline didn't update after a
  new queue was selected.
- Fix a server-side bug that prevented user creation.
- Fix an API bug that exposed the API to CSRF attacks because
  cookie authentication was enabled by default on all endpoints.
This tag has no release notes.