Upspin over WebDAV

[salmān aljammāz]

i pushed a tiny webdav server for upspin to github.com/saljam/upspin-webdav. it uses the golang.org/x/net/webdav package.

it is not a good replacement for upspinfs. most webdav clients make using localhost servers a bit awkward, and securing localhost services against cross-origin request is very tricky. nevertheless, it works at least on some systems so it might be of some use where fuse doesn't work and upsync isn't quite the appropriate model.

i can send a change to the exp repository if people think it's useful to keep it there.

salman