V2.0.1 libanki update

Hi Flavio,
Could you please review these changes. They contain every missed libanki change that I could identify since end of September (most of them are after November).
I left them as separate commits, so that comparison with the relevant anki commit would be easier (the repo and hash of the relevant anki commit are included in each commit message).

Let me know if you have time for this.
Thanks