Enhance testing: run all executables

Add a #! line at the beginning of each of the existing Python programs
and change these files to be executable. This sets the stage for having
the test script blindly run anything that is executable, adding support
for testing many programming languages.

test/test.sh

@@ -11,17 +11,20 @@ files=$(echo *.txt)
 for dir in ../[0-9][0-9]-* ; do
     cd $dir
     for file in $files ; do
-        exe=$(echo tf-[0-9][0-9].py)
-        msg testing $(basename $dir)/$exe with $file
-        python $exe ../$file | diff -b - $mydir/$file
-        result=$?
-        total=$((total+1))
-        if [ $result -ne 0 ]; then
-            failures=$(($failures+1))
-            msg FAILED!
-        else
-            msg passed.
-        fi
+        for exe in * ; do
+            if [ -x $exe ]; then
+                msg testing $(basename $dir)/$exe with $file
+                ./$exe ../$file | diff -b - $mydir/$file
+                result=$?
+                total=$((total+1))
+                if [ $result -ne 0 ]; then
+                    failures=$(($failures+1))
+                    msg FAILED!
+                else
+                    msg passed.
+                fi
+            fi
+        done
     done
     cd $mydir
 done