port isrcsubmit to actual NGS

[JonnyJD]

We have a couple of problems with multi-disc-releases with python-musicbrainz2 and a version that actually works with the webservice 2 somehow would have benefits.

There are two possibilities:

1. Use the webservice directly.
   This might not be the most efficient or sustainable, but there is already a script doing exactly this: isrcsubmit.py (kuno) This is maybe enough or at least a starting point.
2. Use python-musicbrainz3
   We might have to wait until this is usable and actually available for the users. At the mentioned repository I don't see commits since 2010, but there is also a github repo: alastair/python-musicbrainz-ngs

As far as I see, Alastair's library is the most useful, but python-musicbrainz3 is still the official one.
See also:
http://comments.gmane.org/gmane.comp.audio.musicbrainz.devel/4510
http://musicbrainz.1054305.n4.nabble.com/python-musicbrainz3-or-python-wrapper-for-libmusicbrainz-4-td3708264.html

The problem I see with Kuno's version is that it is less robust. As far as I see, you only attach ISRCs to recording-MBIDs. This is not wrong, but you don't see what you actually do. If I would have taken that approach with my script when I started, I would have added many ISRCs in the wrong place without knowing or had to check the IDs on the web.

[JonnyJD]

python-musicbrainzngs (probably will be renamed to python-musicbrainz3) is the way to go. It is in active development and quite promising. The API is not stable yet and it is not packaged anywhere yet.

I don't know yet if that will be a different (forked) script with the same backend or if there will be a version that supports both libraries. That depends on how different the rest of the code is.
Either way, the current version should go into that direction with the code, so it is easier to backport any fixes and features.

[JonnyJD]

alastair/python-musicbrainzngs#52 (libdiscid binding) is crucial if we want to stop using python-musicbrainz2 altogether

Additionally it might be good to go with python3 (when we can drop python-musicbrainz2).

We should probably go and require python-musicbrainz-ngs for isrcsubmit 1.x.

[JonnyJD]

We will use the new python-discid and after some documentation updates we can use python-musicbrainz-ngs just fine.

[JonnyJD]

This works fine now in the master branch, using python-discid and python-musicbrainz-ngs.