Rework Addressing

- Peer now spoofs a NetAddr
- Add PeerGroup, an Array subclass with NetAddr send methods
- Add ServerRegistry, a class which allows peers to share server info; both one per Peer and other configs
- Add PeerGroupManager, a class for syncing groups of Peers or Servers
- Add examples file for above

Signed-off-by: Scott Wilson <i@scottwilson.ca>
Merge branch 'ReworkAddressing-Clean'

Signed-off-by: Scott Wilson <i@scottwilson.ca>