library usage feedback 2

[Николай Шафоростов]

Also, the docs should mention that the only proper way to get TagLib::ID3v2::Tag instance is

TagLib::MPEG::File * file = dynamic_cast<TagLib::MPEG::File*>(_fileRef.file());
TagLib::ID3v2::Tag* id3v2tag=file->ID3v2Tag();
and not
TagLib::ID3v2::Tag* id3v2tag=dynamic_cast<TagLib::ID3v2::Tag*>(_fileRef.tag())
(in this case i get garbage)

i think the bug https://bugs.kde.org/show_bug.cgi?id=164726 is related to this