when removing routes, don't do potentially expensive work once for each route.

We can update solo state and tell interested parties about the removal once the actual removal is done

libs/ardour/session.cc

@@ -3376,8 +3376,6 @@ Session::remove_routes (boost::shared_ptr<RouteList> routes_to_remove)
 				_monitor_out.reset ();
 			}
 
-			update_route_solo_state ();
-            
 			// We need to disconnect the route's inputs and outputs
             
 			(*iter)->input()->disconnect (0);
@@ -3408,14 +3406,14 @@ Session::remove_routes (boost::shared_ptr<RouteList> routes_to_remove)
 					_step_editors--;
 				}
 			}
-
-			RouteAddedOrRemoved (false); /* EMIT SIGNAL */
 		}
     
 		/* writer goes out of scope, forces route list update */
 
 	} // end of RCU Writer scope
     
+	update_route_solo_state ();
+	RouteAddedOrRemoved (false); /* EMIT SIGNAL */
 	update_latency_compensation ();
 	set_dirty();