Mp3tag 3.13

What's new in this version:

New:
- added support for `BARCODE`, `CATALOGNUMBER`, `ISRC`, and MUSICBRAINZ_ALBUMRELEASECOUNTRY` to MusicBrainz tag source
- added option to don't show the message that asks for keeping existing cover art again at Tag Sources confirmation dialog
- added `%_cover_description%` information field

Fixed:
- freedb web search via gnudb.org wasn't working anymore
- pseudorandom number generator used by `$rand()` was not seeded correctly in all cases
- length column was missing from title list at Tag Sources confirmation dialog since v3.12c)
- playlistspecific placeholders were reset when loading new files or directories
- empty file name at export dialog also disabled edit, duplicate, and remove buttons
- cuesheets encoded with UTF8 BOM were written with ANSI encoding
- taskbar icon was missing when starting from File Explorer shell extension under Windows 11 using Standard installation
- apostroph character in export file path caused syntax error
- copying or moving files resulted in inconsistent display of data if overwrite or keep both is used
- configuration files with very long filenames produce runtime error when exporting settings

Changed:
- changed Discogs tag sources to use `CATALOGNUMBER` instead of `CATALOGID` to improve compatibility with other software
- improved sorting performance for large libraries
- added support for editing trackspecific and common metadata at Tag Sources confirmation dialog
- added support for internal resizing via horizontal splitter at Tag Sources confirmation dialog
- added support to enable and disable import of cover art via checkbox at Tag Sources confirmation dialog
- revised Tag Sources confirmation dialog to distinguish between trackspecific and common metadata
- revised Tag Sources confirmation dialog to allow selection of fields to import. (54105
- removed Utils > Compilation option from Tag Sources confirmation dialog which can be realized using an action Guess Values
- added support for using online documentation as internal help
- added workaround for MP4 data atoms with superfluous trailing null byte
- added internal mapping for `MUSICBRAINZ_TRACKID` field
- added support for multivalue MP4 fields written as multiple `data` atoms. (56138
- added confirmation question on editing via file list if the Tag Panel contains unsaved changes and autosaving is not enabled
- added confirmation question on choosing converter, actions, or extended tags if the Tag Panel contains unsaved changes and autosaving is not enabled
- added error reporting to formatting string language
- ensured that characters with accents or umlauts are using the Unicode Normalization Form C when querying Tag Sources
- automatically removing control characters n r t when renaming files and folders
- extended `$validate()` to replace control characters n r t
- added reporting of unsupported or corrupted file structure as error to 'Tag' column
- added workaround for missing padding bytes for INFO subchunks in WAV and AIF
- updated list of default freedb servers to remove invalid servers
- Lng: updated Brazilian Portuguese, Catalan, ChineseCN, Czech, French, Hebrew, Italian, Slovak, Spanish, and Ukrainian translation