Fix: Truncated music-set song names cause warning log.

The music-set does not need to be selected for this to occur.

Resolved by using std::string instead of fixed buffer for song names,
which avoids manual string copying and removes the length limit.

src/base_media_base.h

@@ -289,7 +289,7 @@ enum MusicTrackType {
 
 /** Metadata about a music track. */
 struct MusicSongInfo {
-	char songname[32];       ///< name of song displayed in UI
+	std::string songname;    ///< name of song displayed in UI
 	byte tracknr;            ///< track number of song displayed in UI
 	const char *filename;    ///< file on disk containing song (when used in MusicSet class, this pointer is owned by MD5File object for the file)
 	MusicTrackType filetype; ///< decoder required for song file