Moved legacy code into archive, ready for a new rapid(?) prototype.

I may regret doing this!

archive/unit-tests/nil.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+expected=nil
+actual=`echo 'nil' | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+    exit 0
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    exit 1
+fi