OCaml Compiler Hacking Event

@dannywillems @objmagic Thanks both for the suggestion, it is a little out of date. We added some “newer” topics/projects for this event at the top as a temporary measure, but I think it would be great to get the list updated and get more people to feed back to it directly with progress.

It might be that the list would benefit from being more generalisable, i.e. not specific to the Cambridge meetup.