Improve wifi handling part two.

If a route is removed, RouteFragment goes into deviceListMode. This change
makes it go back into playlistMode if the route set in MediaRouterPlayService
is added again.

src/com/github/nutomic/controldlna/gui/RouteFragment.java

@@ -244,6 +244,10 @@ OnSeekBarChangeListener, OnScrollListener {
 						break;
 					}
 				mRouteAdapter.add(route);
+
+                RouteInfo current = mMediaRouterPlayService.getCurrentRoute();
+                if (current != null && route.getId().equals(current.getId()))
+                    playlistMode(current);
 			}
 
 			@Override