Add first asym implementation

Move test code to pssTest.go
Minor changes

cmd/pssTest/psstest.go

@@ -2,7 +2,10 @@ package main
 
 import (
 	"fmt"
+	"os"
+	"time"
 
+	"github.com/ethereum/go-ethereum/log"
 	swarm "github.com/vocdoni/go-dvote/net/swarm"
 )
 
@@ -13,5 +16,20 @@ func main() {
 		fmt.Printf("%v\n", err)
 		return
 	}
-	sn.Test()
+	key := "randomkey0"
+	sn.PssSub("sym", key, "vocdoni_test", "")
+
+	go func() {
+		for {
+			msg := <-sn.PssTopics["vocdoni_test"].Delivery
+			fmt.Printf("Pss received: %s\n", msg)
+		}
+	}()
+
+	hostname, _ := os.Hostname()
+	for {
+		err := sn.PssPub("sym", key, "vocdoni_test", fmt.Sprintf("Hello world from %s", hostname), "")
+		log.Info("pss sent", "err", err)
+		time.Sleep(10 * time.Second)
+	}
 }