Merging swift-corelibs-foundation PRs

Hi everyone,

I’m going through our open PRs for swift-corelibs-foundation and merging what I can. I’m sorry that some of them have been outstanding for so long - my time has been consumed with the value types work you recently saw on swift-evolution and a lot of other things.

Most of these need merging now due to changes in the language in the meantime, and I’m doing that where possible. If you have one outstanding and you want to rebase it yourself that will help too.

I want to get us to a point where the only outstanding PRs are ones that are waiting on something like changes in other repos or the grand libdispatch integration.

- Tony