Complete reworking of the REPL

which is good in itself, but not what I was meant to be working on.

unit-tests/eval-real.sh

@@ -5,12 +5,11 @@ expected='5.05'
 actual=`echo "(eval 5.05)" |\
   target/psse 2> /dev/null |\
   sed 's/0*$//' |\
-  head -2 |\
   tail -1`
 
+# one part in a million is close enough...
 outcome=`echo "sqrt((${expected} - ${actual})^2) < 0.0000001" | bc`
 
-
 if [ "${outcome}" = "1" ]
 then
     echo "OK"