strip out all ICMP network code and begin gossip refactor for attestations (#256)

* strip out all ICMP code and begin gossip refactor

* validate incoming statements

* message_allowed logic

* compiles

* do reporting and neighbor packet validation

* tests compile

* propagate gossip messages

* test message_allowed

* some more tests

* address grumbles

polkadot/service/src/lib.rs

@@ -272,7 +272,7 @@ construct_service_factory! {
 
 				let gossip_validator_select_chain = select_chain.clone();
 				let gossip_validator = network_gossip::register_validator(
-					&*service.network(),
+					service.network(),
 					move |block_hash: &Hash| {
 						use client::BlockStatus;