made stop and start network follower return well formed errors when called...

made stop and start network follower return well formed errors when called while the follower is not in the correct status.

api/client.go

@@ -392,6 +392,11 @@ func (c *Client) StartNetworkFollower(timeout time.Duration) (<-chan interfaces.
 	jww.INFO.Printf("StartNetworkFollower() \n\tTransmisstionID: %s "+
 		"\n\tReceptionID: %s", u.TransmissionID, u.ReceptionID)
 
+	if c.status.get() != Stopping{
+		return nil, errors.Errorf("Cannot Start the Network Follower when it is not stopped")
+	}
+
+
 	c.clientErrorChannel = make(chan interfaces.ClientError, 1000)
 
 	cer := func(source, message, trace string) {
@@ -450,6 +455,11 @@ func (c *Client) StartNetworkFollower(timeout time.Duration) (<-chan interfaces.
 func (c *Client) StopNetworkFollower() error {
 	c.followerLock.Lock()
 	defer c.followerLock.Unlock()
+
+	if c.status.get() != Running{
+		return errors.Errorf("Cannot Stop the Network Follower when it is not running")
+	}
+
 	err := c.status.toStopping()
 	if err != nil {
 		return errors.WithMessage(err, "Failed to Stop the Network Follower")