lazy-extractors: Fix after commit 6e6b9f600f2f447604f6108fb6486b73cc25def1

lazy-extractors: Fix after commit 6e6b9f600f2f447604f6108fb6486b73cc25def1

The problem was in the following code:

    class ArteTVPlus7IE(ArteTVBaseIE):

        ...

        @classmethod
        def suitable(cls, url):
            return False if ArteTVPlaylistIE.suitable(url) else super(ArteTVPlus7IE, cls).suitable(url)

And its sublcasses like ArteTVCinemaIE.

Since in the lazy_extractors.py file ArteTVCinemaIE was not a subclass of ArteTVPlus7IE, super(ArteTVPlus7IE, cls) failed.

To fix it we have to make it a subclass. Since the order of _ALL_CLASSES is arbitrary we must sort them so that the base classes are defined first. We also must add base classes like YoutubeBaseInfoExtractor.