Do not set any deadlines in websocket connection

* The websocket rfc doesn't specify what to do when a client doesn't
  respond to a ping message. It just states that it must respond with a
  pong message. But it is unclear what should happen when the client
  doesn't respond with a pong message. So instead of closing the
  connection, we are keeping the connection open as long as possible.

src/api/api.go

@@ -307,8 +307,7 @@ func (a *Api) handleSignalReceive(ws *websocket.Conn, number string) {
 
 func wsPong(ws *websocket.Conn) {
 	ws.SetReadLimit(512)
-	ws.SetReadDeadline(time.Now().Add(pongWait))
-	ws.SetPongHandler(func(string) error { ws.SetReadDeadline(time.Now().Add(pongWait)); return nil })
+	ws.SetPongHandler(func(string) error { log.Debug("Received pong"); return nil })
 	for {
 		_, _, err := ws.ReadMessage()
 		if err != nil {
@@ -322,7 +321,6 @@ func wsPing(ws *websocket.Conn) {
 	for {
 		select {
 		case <-pingTicker.C:
-			ws.SetWriteDeadline(time.Now().Add(writeWait))
 			if err := ws.WriteMessage(websocket.PingMessage, []byte{}); err != nil {
 				return
 			}