feat: install moo and use in toy example (#2)

I failed to find a satisfactory way to compile and import moo.js with
  fixed specifiers, so finally I just gave up and patched the distributed
  moo code to be an es6 module. Very ugly but it works.

Resolves #1.

Reviewed-on: #2
Co-authored-by: Glen Whitney <glen@studioinfinity.org>
Co-committed-by: Glen Whitney <glen@studioinfinity.org>

etc/testscript.html

@@ -5,8 +5,8 @@
     <title>vrml1to97 test</title>
     <script>
       (async () => {
-        const vrml1to97 = await import('../dist/index.js')
-        console.log(vrml1to97.convert('test'))
+        const vrml1to97 = await import('../dist/vrml1to97/index.js')
+        console.log(vrml1to97.convert('if (moo) cows // hurray'))
       })()
     </script>
   </head>