Use an interruptible sleep to allow our threads to exit sooner

src/VideoStream.c

@@ -60,10 +60,10 @@ static void UdpPingThreadProc(void* context) {
 
         // Send less frequently if we've received data from our peer
         if (receivedDataFromPeer) {
-            PltSleepMs(5000);
+            PltSleepMsInterruptible(&udpPingThread, 5000);
         }
         else {
-            PltSleepMs(500);
+            PltSleepMsInterruptible(&udpPingThread, 500);
         }
     }
 }