Fix a few issues (#48)

* Fix a few issues

* Make sure that adding a dispatch return event to a node stream creates the stream if needed.
  This could cause jobs that are added right on startup to fail to be dispatched.
* Fix potential panic in cleanup goroutine when the pending jobs map contains nil values
* Make sure to close all maps when closing the node.
* Properly log event information when discarding stale ack events.
* More consistent logging

* Fix a few additional issues

* Ensure stale node streams are gced
* Make close and shutdown code cleaner
* Cleanup all maps properly on node close

examples/streaming/multi-sinks/main.go

@@ -54,7 +54,7 @@ func main() {
 	}
 
 	// Don't forget to close the sink when done
-	defer sink1.Close()
+	defer sink1.Close(ctx)
 
 	// Read and acknowlege event
 	ev := <-sink1.Subscribe()
@@ -70,7 +70,7 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
-	defer sink2.Close()
+	defer sink2.Close(ctx)
 
 	// Read second event
 	ev = <-sink2.Subscribe()

examples/streaming/multi-streams/main.go

@@ -40,7 +40,7 @@ func main() {
 	}
 
 	// Don't forget to close the sink when done
-	defer sink.Close()
+	defer sink.Close(ctx)
 
 	// Subscribe to events
 	c := sink.Subscribe()

examples/streaming/pub-sub/main.go

@@ -56,7 +56,7 @@ func main() {
 	}
 
 	// Don't forget to close the sink when done
-	defer sink.Close()
+	defer sink.Close(ctx)
 
 	// Read both events
 	c := sink.Subscribe()

examples/streaming/single-sink/main.go

@@ -45,7 +45,7 @@ func main() {
 	}
 
 	// Don't forget to close the sink when done
-	defer sink.Close()
+	defer sink.Close(ctx)
 
 	// Consume event
 	ev := <-sink.Subscribe()