Bartosz Polaczyk

Store file permissions in zipFiles

1

Add support for storing file permissions, whenever available. The unzipping part already covers that. This is a zipping counterpart for #73 and #74

`Unbox` lacks support for enums that have custom `RawRepresentable` that is expressible by literals. I needed that in my library [EnumList](https://github.com/polac24/EnumList/), but maybe we could integrate it to `Unbox` library?

Investigate how to overcome a limitation for DispatchSourceTimer

To not force static dispatch on a protocol extension (since `allRawValues` is a PE), define it in a protocol definition.