added initial code for random VCD generator

bin/vcd-gen.js

@@ -0,0 +1,41 @@
+#!/usr/bin/env node
+'use strict';
+
+const $version = () => '$version Generated by VerilatedVcd $end\n';
+
+const $date = () => '$date Wed Sep 18 22:59:07 2019 $end\n';
+
+const $timescale = () => '$timescale 1ns $end';
+
+const randomScope = () => {
+  return {
+    top: {
+      clock: '"}G',
+      fruit: {
+        point: 'u)'
+      },
+      leaf: {
+        counter: '{u'
+      }
+    }
+  };
+};
+
+const definitions = () => '';
+
+const simulation = () => '';
+
+
+const main = seed => {
+  const scope = randomScope(seed);
+  return (
+    $version() +
+    $date() +
+    $timescale() +
+    definitions(scope) +
+    '$enddefinitions $end\n' +
+    simulation(scope)
+  );
+};
+
+console.log(main());