Sundry tweaks to aos/vision libs

Change-Id: Ia5578dcf2d42ac53b81af239bf329eb084fcf1d9
diff --git a/aos/vision/events/udp.cc b/aos/vision/events/udp.cc
index b5367f6..4c0437b 100644
--- a/aos/vision/events/udp.cc
+++ b/aos/vision/events/udp.cc
@@ -22,7 +22,8 @@
 }
 
 int TXUdpSocket::Send(const char *data, int size) {
-  return PCHECK(send(fd_.get(), data, size, 0));
+  // Don't fail on send. If no one is connected that is fine.
+  return send(fd_.get(), data, size, 0);
 }
 
 RXUdpSocket::RXUdpSocket(int port)