fix glitch in fft.c and add scripts to display data sets without temp file

- usrp/doall: new script to directly evaluate and plot data sets
- usrp/fft.c (fft_complex): don't square the magnitude
- usrp/plscan: if an argument name has the form title=name, use "name" as
  the file name and "title" as the title

usrp/doall

@@ -0,0 +1,11 @@
+#!/bin/bash -x
+opts=
+while [ "$2" ]; do
+    opts="$opts $1"
+    shift
+done
+a=
+for n in $1; do
+    a="$a `basename $n`=<(./evscan $n)"
+done
+eval ./plscan $opts $a

usrp/fft.c

@@ -32,7 +32,7 @@ static void fft_complex(int n, const float *re, const float *im, double *res)
 
 	for (i = 0; i != n; i++) {
 		a = hypot(out[i][0], out[i][1])/n;
-		a = a*a;
+//		a = a*a;
 		res[i] = a;
 	}
 }

usrp/plscan

@@ -24,7 +24,14 @@ set title "Received signal strength"
 set data style errorlines
 plot \
   `for n in $@; do
-     echo -n $comma \'$n\' title \'${n%.*}\'
+     if [ "$n" = "${n#*=}" ]; then
+	file=$n
+	title=${n%.*}
+     else
+	file=${n#*=}
+	title=${n%%=*}
+     fi
+     echo -n $comma \'$file\' title \'$title\'
      comma=,
    done`
 EOF