v2.0.0

Next major release. Planned on GitHub Project #3 (field "Cible" = 2.0): audio analysis (reliable tempo + energy, beat grid, key detection), file quality (fake lossless detection, replace a file with a better copy keeping its history), interface (sidebar pins, Continue listening, custom accent colour, theater mode, settings diff/reset), native Linux (GTK frontend, XDG portal dialogs), DLNA, and the lyrics editor.