Add support for writing more Ogg tags.

This propagates more of the data between a vlc_meta_t object and
the taglib object used to write out new metadata. This should
support everything except Setting, URL, NowPlaying, ArtworkURL, and
TrackID.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
Support alternate TrackTotal styles in taglib.

vorbis_ParseComment() supports several different methods of
specifying the total number of tracks. Update the taglib module
to support reading in the same set.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
Sort Xiph tag checks.

This places them in the same order as they appear in vlc_meta.h to
make it easier to see which ones are present and which ones are
missing.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
Qt: move validators
Qt: use validator for clipboard input
Add support for parsing more Ogg tags.

This fills in the initial vlc_meta_t object with more of the fields
it knows about, ensuring fields that we can edit with taglib don't
show up in the 'Extra metadata' panel.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>