libsaria: Fix queue num_visible()

When songs are removed from the queue, they should also be removed from
the visible set, otherwise num_visible() will never change.

libsaria/sources/queue/__init__.py

@@ -6,9 +6,15 @@ import queue
 
 visible = set()
 
-# Function pointers for convenience
-rm_ids = queue.rm_ids
-reset  = queue.reset
+def rm_ids(ids):
+	global visible
+	visible = visible - set(ids)
+	queue.rm_ids(ids)
+
+def reset():
+	global visible
+	visible = set()
+	queue.reset()
 
 def list_ids():
 	for id in queue.queue_list:
@@ -29,5 +35,8 @@ def num_visible():
 	return len(visible)
 
 def next():
-	return queue.pop()
+	id = queue.pop()
+	if id != None:
+		visible.remove(id)
+	return id