[2.x.x] deserialization now protocol version aware (#2824)

* introduce protocol version to deserialize and read

* thread protocol version through our reader

* example protocol version access in kernel read

* fix our StreamingReader impl (WouldBlock woes)

* debug log progress of txhashset download

api/src/types.rs

@@ -83,7 +83,7 @@ pub struct Status {
 impl Status {
 	pub fn from_tip_and_peers(current_tip: chain::Tip, connections: u32) -> Status {
 		Status {
-			protocol_version: p2p::msg::ProtocolVersion::default().into(),
+			protocol_version: ser::ProtocolVersion::default().into(),
 			user_agent: p2p::msg::USER_AGENT.to_string(),
 			connections: connections,
 			tip: Tip::from_tip(current_tip),