- internal nullptr checks
- prevent modifications to network_address (shallow copy issues)
- automagically works with any type containing interface functions
- removed fnv1a hashing
- ipv4_network_address now flattened with no base class
All code which was using ip and port now uses a new IPv4 object,
subclass of a new network_address class. This will allow easy
addition of I2P addresses later (and also IPv6, etc).
Both old style and new style peer lists are now sent in the P2P
protocol, which is inefficient but allows peers using both
codebases to talk to each other. This will be removed in the
future. No other subclasses than IPv4 exist yet.
