Mp3tag 3.07

What's new in this version:

Fixed:
- regression to a possible runtime error when running actions that result in empty fields (since v3.05f)
- drawing artifacts when resizing columns and splitter at tag-sources results
- suggest sorting of tag-sources result by length was still flaky
- sorting tag-sources result by length did not work correctly if length column exceeded the one hour mark
- occasional crash after using the extended tag dialog due to heap corruption
- occasional cannot write to file error when editing tags via navigation in the file list (since v3.05a)
- layout problem where dropdown fields on Tag Panel were sometimes partially hidden behind vertical scrollbar

Changed:
- using special filenames `cover` and `back` for front and back covers at Matroska attachments
- re-added ACOUSTID_FINGERPRINT to list of standard fields on new installations or field-list reset
- removing Matroska segment title if it differs from global tag title
- added POPULARIMETER and RATING to list of standard fields
- creating multiple fields using the multiple fields delimiter `\` via replace or other actions was not possible
- not using ID3v2 unsynchronization scheme anymore when writing ID3v2.4 due to compatibility reasons with apps that don't implement the standard

New:
- added option to configure the image quality when resizing cover art via 'Adjust cover'
- added advanced tagging option to always display POPULARIMETER field for ID3v2 rating instead of app-specific convenience fields
- added support for editing cover art for Matroska MKA/MKV tags
- added support for WebP images for cover art
- added support for MP4 fields ITUNESALBUMID, ITUNESARTISTID, ITUNESCOMPOSERID, ITUNESCOUNTRYID, ITUNESGENREID, and XID
- LNG: updated Brazilian Portuguese, Czech, Finnish, Italian, Portuguese, Swedish, and Turkish translation