message: add a test for pid monitoring
diff: @@ -22,6 +22,16 @@ if [ "$?" -ne "0" ]; then
  exit 1
  fi
  +perl -e ' do {} until (0)' &
  +test_pid="$?"
  +./pcm -pid $test_pid -- sleep 1
  +if [ "$?" -ne "0" ]; then
  + echo "Error in pcm"
  + kill $perl_pid
  + exit 1
  +fi
  +kill $test_pid
  +
  ./pcm -r 0.1 -csv=pcm.csv -- sleep 5
  if [ "$?" -ne "0" ]; then
  echo "Error in pcm"
  