Adding support for the Publisher (record-label) metadata tag

Adding support for id3 TPUB and ogg/flac PUBLISHER. These tags reference the record label that published the album/recording.

* ID3 v2 -> http://id3.org/id3v2.3.0
* Vorbis -> https://xiph.org/vorbis/doc/v-comment.html and http://age.hobba.nl/audio/mirroredpages/ogg-tagging.html for the Vorbis container defs. Original vorbis specs state ORGANIZATION is the noted tag, but it seems the community has standardized on PUBLISHER (which has been used here).

Tests for ogg/flac were updated (along with the binaries), but i was not able to successfully update the MP3 containers, so i have left those tests untouched. Though here is a sample run against an Id3v2.3 container.

```
$ go run taggo.go /mnt/media/Audio/Electronic/Singles/House/A_to_G/Blunted_Dummies-House_For_All_Remixes-\(DEFDIG1124\)-2011-jW/
Blunted Dummies - House For All Remixes - House for All (John Acquaviva Original 2011 Edit) [#0.01] [06:10] [MP3/320kbps/16bit/44kHz] [Definitive Recordings]
Blunted Dummies - House For All Remixes - House for All (Olivier Giacomotto Remix) [#0.02] [07:05] [MP3/320kbps/16bit/44kHz] [Definitive Recordings]
Blunted Dummies - House For All Remixes - House for All (Superskank Remix) [#0.03] [06:35] [MP3/320kbps/16bit/44kHz] [Definitive Recordings]
```

Great work. This is much nicer than the standard taglib c extension libraries!