prototype: rename channel.Target() -> channel.Peer() for clarity

There was some discussion whether PeerName() would be a better method
name instead. I believe that we don't need to have PeerName(), given
that we already don't return the original peer reference. Peer() should
suffice...
Revert "prototype: use UUID v1"

This reverts commit 725b99652958750ea3dc5df72d4de287a8c9c593.

Conflicts:
	prototype/dpx/peer.go