[Session] Add thread sleep when waiting for buffer

When you are waiting for buffer, the VP do DemuxRead callbacks in very fast way
causing CPU spikes until 13% (on a fast CPU)
add a thread sleep help to mitigate the problem

Author: CastagnaIT

src/Session.cpp

@@ -828,6 +828,8 @@ bool SESSION::CSession::GetNextSample(ISampleReader*& sampleReader)
 
   if (waiting)
   {
+    // Prevents CPU usage spikes due to continuous Kodi VP requests
+    std::this_thread::sleep_for(std::chrono::milliseconds(10));
     return true;
   }
   else if (res)