add id and address to Node#inspect
require node_registry
add shortcut to the local node
add method dispatch to Node
move local dispatch behavior to LocalNode

LocalNode encapsulates the local dispatching behavior of the local node
as distinct from a remote node. It may go away if there's too much
shared behavior with Node.
rename Node to RemoteNode
don't require that a node id has been set to get the local node

The special node key :_local always gets the local node. The node id is
only used so things like routers can dispatch messages to nodes without
caring whether they are local or not.
fill in LocalNode#cast
check for the _local key correctly
always use symbols as keys in Registry
terminate socket monitors if their sockets close
terminate socket monitors if their sockets close
publish to remote notifer async
set identity when connecting to a peer
reset connects as well when identity changes