Playlist system creation

Added a way to deal with playlist. Also now autoscroll to keep new playing kara on top. Fixed wrong command name

instance/views/menu/queue.ejs

@@ -3,6 +3,7 @@
 <div class="dropdown-menu dropdown-menu-sm" id="context-menu-right">
     <a class="dropdown-item" id="queue-pause"    href="#">Pause playback</a>
     <a class="dropdown-item" id="queue-play"   href="#">Resume playback</a>
+    <a class="dropdown-item" id="queue-recenter"   href="#">Recenter queue</a>
     <div><hr class="dropdown-divider"></div>
     <a class="dropdown-item" id="queue-find"    href="#">Find kara</a>
     <div><hr class="dropdown-divider"></div>