Fix '/register' bugs

* New classification was inserted twice into the array.
* If the program had a new tv-series-name, it's _id wasn't set, since program had been saved before the parent was created.

Using a "manual" changelog call for the update, with a fixed-string status. It's not worth it saving the exact same data in the changelog as is in the 'versioned' classifications array.
When a program has no classifications yet, only kavi and owner of the draft can finish the classification
Clear drafts on /register and handle classification editing conflicts

When a classification is registered we clear all drafts. If another user is on the classification editing page, they are notified of the conflict on first autosave or register-button click.