Restricting number of weeks to 4 (end-of-year corner case)
If you're editing an archived project, you get a nice fat warning title
Prevent editing of invoices on archived projects
Modified permission checks to account for archived projects/persons
Showing archived state when applicable
Archived persons are no longer editable on team page
Adjusted headings
Got booking filtering to work.

- Archived projects aren't bookable.

- Not-yet-active or not-active-anymore projects aren't bookable.

- You can only book in the current year
Allowing bookings in the next year, only not in the previous ones.
Added comment
Added totals to booking page