Respin: upspin revival

tl;dr: I revived the upspin project source code. See it at https://github.com/filmil/upspin, and https://github.com/filmil/upspin-gdrive. Read on to learn what that actually means. History Upspin was a project intended to provide a global namespace for all digital artifacts. It ended up mostly being used as a distributed file store, although the idea was more general than that. It was quite useful…