made the bindings not allow multiple calls of login

bindings/callback.go

@@ -96,3 +96,17 @@ func newRoundListUnregister(rounds []id.Round, ec []*dataStructures.EventCallbac
 type ClientError interface {
 	Report(source, message, trace string)
 }
+
+
+type LogWriter interface{
+	Log(string)
+}
+
+type writerAdapter struct{
+	lw LogWriter
+}
+
+func (wa *writerAdapter)Write(p []byte) (n int, err error){
+	wa.lw.Log(string(p))
+	return len(p), nil
+}

bindings/client.go

@@ -137,6 +137,11 @@ func LogLevel(level int) error {
 	return nil
 }
 
+//RegisterLogWriter registers a callback on which logs are written.
+func RegisterLogWriter(writer LogWriter){
+	jww.SetLogOutput(&writerAdapter{lw:writer})
+}
+
 //Unmarshals a marshaled contact object, returns an error if it fails
 func UnmarshalContact(b []byte) (*Contact, error) {
 	c, err := contact.Unmarshal(b)