feat: install moo and use in toy example

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
   code to be an es6 module. A bit ugly but it works.

.gitignore

@@ -1,6 +1,7 @@
 # Object files
 build
 dist
+deps
 
 # Editor backups
 *~