Complete reworking of the REPL

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

unit-tests/empty-string.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 expected="\"\""
-actual=`echo '""' | target/psse 2> /dev/null | head -2 | tail -1`
+actual=`echo '""' | target/psse | tail -1`
 
 if [ "$expected" = "$actual" ]
 then