* lib/configuration.py: Use 'node' instead of 'peer'

* lib/network.py: No #ERR anymore, we simply (still) send back proper JSON messages, though unencrypted.
  I don't really see a way around this if key exchange has not (yet) completed.

* lib/overlay.py: Properly implement join/leave.

* lib/shell.py: Update with skeleton leave command.
Merge branch 'master' of github.com:windelbouwman/jodawg