Different media/tag formats specify languages and countries
differently. This change introduces a Locale class to keep track
of the format being used. So far there are no automatic conversions
implemented so it is entirely up to the user to pass valid values using
a format which matches the one required by the media/tag format.
This change also adds support for Matroska's IETF elements so at least the
raw value can be read, written and is preserved.
FLAC stores tags on track level. Hence we must parse the
tracks here in order to parse the tags. This hasn't been taken
into account when refactoring the tag editor CLI leading to
https://github.com/Martchus/tageditor/issues/36.
So let's handle these format specific details in the tagparser
library which will now internally parse tracks when calling
parseTags() on FLAC files.
This also fixes the weird behavior to consider tags supported
although the container format is unknown.
Martchus