This was a bit sloppy. In some cases, we had the config fiel lock,
but that that does not protect against config_Put*(). In some cases,
the lock was only taken for strings but not float/integers.

Another VLC instance could get a corrupt configuration otherwise.

This leaves the choice for bindings to use it or not.

I wish we did the same for hotkeys and inhibit but it would break
backward libvlc API compatibility.

It will avoid memory corruptions in case of a broken decoder.

It probably closes #2719.

Butw ithout it, the layout of multichannels audio are probably wrong.

Maybe we should split encoders per ES type?

These calls have been replaced by vlc.playlist.items.* calls.