Add more dropped id3v2 tags and short-key translation to mkogg.py.

Add more dropped id3v2 tags and short-key translation to mkogg.py.

The occurence of three-charachter short tag keys may be due to the
version 0.1.11 -> 0.1.12 transition in the id3v2 utility.  In any
case, the new translation dictionary makes it easy to map new keys
onto already existing synonyms.

Also, we no longer attempt to parse the 'no id3v1 tag' message as if
it were another tag.