Update ID3v1 genre list

https://bugzilla.gnome.org/show_bug.cgi?id=729036
Read extended Winamp 5.6 genres stored as integers

As libid3tag has not been updated in some time, the genre list is rather
out of date. If an integer genre is found, and libid3tag does not find
it in the index, try the EasyTAG index as a fallback.