NEW:

- #196 Add "w.bibliotece.pl" as a source for Polish language books.
  See the project documentation for extra details.
- #198 Allow choosing a different bookshelf as a default.
  This finally allows users to delete the "My Books" (also known as "1st") bookshelf.
- the tag-substitution rules now support automatic removal of unwanted tags during searches.
- preserve ISBN-10 codes in search results even when searching by ISBN-13 code.
- support for directly importing Book-Catalogue _bcbk_ files.
