Racket 5.3.5

I've had a look at this, and I'm not exactly sure what we should be
linking here. Input from a user would be helpful.
Merge pull request #552 from fanquake/racket-5-3-5

Racket 5.3.5
Add Onyx 10.8
Update Onyx
Merge pull request #618 from srod/onyx-108

Add Onyx 10.8