update peers spec, tweak map style

- move connectivity.peers into top-level peers field
- consolidate peers.current and peers.lifetime into peers
- give each peer "connected" field to indicate if currently connected
- give each peer "lastConnected" field for time last connected to that peer
- move "name" and "email" into "rosterEntry" field, which should also contain the other roster fields

- color stroke (outline) rather than fill of countries by number of give vs. get mode peers