usrp/sps/: added peak power summary graph

- vizp: plot the peak power
- row: retrieve peak power from "viz" (with -m) and use it to generate the
  summary
- vizr: corrected typo in prefix argument number

usrp/sps/vizr

@@ -30,7 +30,7 @@ done
 [ "$2" ] || usage
 [ "$3" ] && usage
 
-prefix=$3
+prefix=$1
 file=$2
 
 gnuplot -persist <<EOF