Hide track number while song is currently playing/paused/loading, mimicking native player
Fix colors for track, index number in playlists and albums
Merge branch 'pr/134'

* pr/134:
  Fix colors for track, index number in playlists and albums
  Hide track number while song is currently playing/paused/loading, mimicking native player
Pref. to show playing status in mini player icon (fixes #136)