Log what peer failed clock-sync

When a peer isn't running to perform a clock-sync, we should log which one it
was.
Improve logging for vnode

Prepend the host, port and partition in front of all log messages in
skuld.vnode
Add more logging for node
Deal with ids that contain slashes

The base64 encoding that is used for ids does not play nicely with the HTTP
route matching unless a regex is specified.
Merge branch 'improve-logging-for-vnode' into travis-random-testing
Merge branch 'log-peer-for-clock-sync-exceptions' into travis-random-testing