Show tracks + duration of album, playlist, queue

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Fixes #475

src/ui/album.rs

@@ -66,6 +66,17 @@ impl ViewExt for AlbumView {
         format!("{} ({})", self.album.title, self.album.year)
     }
 
+    fn title_sub(&self) -> String {
+        if let Some(tracks) = &self.album.tracks {
+            let duration_secs: u64 = tracks.iter().map(|t| t.duration as u64 / 1000).sum();
+            let duration = std::time::Duration::from_secs(duration_secs);
+            let duration_str = crate::utils::format_duration(&duration);
+            format!("{} tracks, {}", tracks.len(), duration_str)
+        } else {
+            "".to_string()
+        }
+    }
+
     fn on_command(&mut self, s: &mut Cursive, cmd: &Command) -> Result<CommandResult, String> {
         self.tabs.on_command(s, cmd)
     }