Add 2 more tag lists to Options / Tags and ...

1. Enhance encoding default - updates if you change id3v2 versions
2. Fix autocomplete tag lists (still using ' ' rather than ', ' as separator when selecting from completer list).
Improve ability to save / clear existing tags.

Prior to this PR, we could only either keep / clear all existing tags
(rather than individual tags)  or preserve (i.e. not allow MB to
overwrite) specific tags.

This PR provides the following:
1. Improved granularity for keeping / clearing tags. Additional fields
in Options / Tags, unhandled ID3 tags put into ~id3:XXXX variables.
2. Support for * suffix matching on Keep/Clear/Preserve tag lists.