Clear separation of ID3v1 and v2 tags

[aw-was-here]

Is your feature request related to a problem? Please describe. Related to #260 , I've noticed that the ID3v1 tags are usually wrong/not what was intended by the user since MP4 files are post-ID3v2. Thus the merging of v1 and v2 genre information is a bit of a problem.

Describe the solution you'd like TinyTag should have a way to know which format was used for which genre information. Splitting this information would allow for applications to make an intelligent choice as to which one to use.

Describe alternatives you've considered Another choice here is to have a flag or something to tell TinyTag to ignore ID3v1 genre information altogether. In some ways, that's a better solution since we all know how problematic that genre information might be.

Additional context