// Abstract base class (interface) for a channel; also used for the master container.
// This lets us arrange channels into a call hierarchy.
-// We maintain a h
eirarchy of notification channels; events are always started at the top
+// We maintain a hirarchy of notification channels; events are always started at the top
// and propagated through the hierarchy only if they pass a filter.
// Any channel can be created with a parent. A null parent (empty string) means it's
// tied to the root of the tree (the LLNotifications class itself).