Allow multiple for more fields

[platelminto]

Some fields could have multiple matches, and currently just throw away the others (e.g. audio, quality). They should give all of them, and become just list types.

This could be done by, rather than just ignoring and adding the match indices when the given field already exists, check if it's a significant other one (i.e. not just because the regex for one also matches another, which currently makes the order of regexes for each field in patterns.py important - would be nice to make the order not matter), and if yes add it.

This opens up the possibility of generalising list types, rather than the current custom regexes and methods that fields like genre, language, etc. must have.