fix #1060
ftintitle unit tests
feat_tokens: change argument name, fix regex flag
fix flake8
Remove migration docs
Mention #130 in docs
remove capturing parentheses
Use a non-capturing group by default (#1060)

Now clients don't have to decide whether they need parentheses or not.
Simplify word boundaries (#1060)

Use lookahead/lookbehind matching to ensure there is whitespace around the
token. Replaces the use of \b, which doesn't work for "ft.", etc.
More flexible title splitting (#1060)

These tokens should not be artist-exclusive.
Changelog for #1143, fix #1060
Added an option for the import command to print the names of the files to import instead actually importing them.
Some refactoring for better code structure
Added an interface for plugins to filter imported files
Did some changes to use the latest beets source with the enumerate-only option and the file filter.
Some changes for the code structure
Some changes to meet the flake8 rules