Audacious - OLD, PLEASE USE GITHUB DISCUSSIONS/ISSUES

The song info window of the Qt UI could be made into a much more useful tag editor with some improvements.

Some ideas:

1. Make field values editable with a single click; the current behavior ("click twice slowly") is awkward
2. Allow navigating between fields with the Up and Down arrow keys while editing
3. Enable the "Save" button only when changes are made, and disable again once successfully saved
4. Add a "Revert" button to go back to on-disk values, and enable/disable with the "Save" button
5. Display unsaved changes in bold text until saved

Bonus goal -- allow displaying/editing tags of multiple files at once (by selecting multiple files before pressing Alt-I):

• We could do a cool stack/overlay of multiple album art images in place of the single image display
• The path label could just display something like "8 files selected"
• Set the text of the "Save" button to "Save 8 files" just to be extra clear
• Fields that were identical between all tags would be displayed and editable like normal
• Fields that differed between tags should be display disabled text like "Various; press Delete to clear all"
• Pressing the Delete key would clear the existing, different values and allow editing those fields