Feature request: restore metadata during extraction

[jfly]

I can't tell if this has already been discussed elsewhere.

In #63, it looks like we started capturing metadata, but AFAICT, we don't actually restore that metadata on extraction. I can't tell if this was intentional. It looks like this would be fairly straightforward to implement with rust's std::fs::File::set_times function.

I'd be happy to send in a PR implementing this if you're open to it.