Fix CPU use (#40)

* Move default case out of select block.
* Add defers to close resources.
* `go fmt` cleanup.

ping.go

@@ -286,6 +286,7 @@ func (p *Pinger) run() {
 
 	var wg sync.WaitGroup
 	recv := make(chan *packet, 5)
+	defer close(recv)
 	wg.Add(1)
 	go p.recvICMP(conn, recv, &wg)
 
@@ -295,7 +296,9 @@ func (p *Pinger) run() {
 	}
 
 	timeout := time.NewTicker(p.Timeout)
+	defer timeout.Stop()
 	interval := time.NewTicker(p.Interval)
+	defer interval.Stop()
 
 	for {
 		select {
@@ -316,7 +319,7 @@ func (p *Pinger) run() {
 			if err != nil {
 				fmt.Println("FATAL: ", err.Error())
 			}
-		default:
+		}
 		if p.Count > 0 && p.PacketsRecv >= p.Count {
 			close(p.done)
 			wg.Wait()
@@ -324,7 +327,6 @@ func (p *Pinger) run() {
 		}
 	}
 }
-}
 
 func (p *Pinger) Stop() {
 	close(p.done)