- Support headers in fetch()
- Adds many async fs functions:
  deno.rename() deno.remove(), deno.removeAll(), deno.removeSync(),
  deno.removeAllSync(), deno.mkdir(), deno.stat(), deno.lstat()
  deno.readFile() and deno.writeFile().
- Add mode in FileInfo
- Access error codes via error.kind
- Check --allow-net permissions when using fetch()
- Add deno --deps for listing deps of a script.