Avoid serialization of internal properties

Current serialization algorithm don't support internal properties refs.
So we can't inspect in console something like this:
`console.log(console)` (tested on 0.11.13)
Typo, should be `serialization` and `doesn't support`.

I prefer to add a space after a double-slash (`// Current...` instead of `//Current...`), but it's not a big deal.