Introduce a Proof-of-Validation block type and use that in place of BlockData (#227)

* validators expect collators to give them parachain messages

* mostly port network to use pov_block

* network tests pass

* verify ingress when fetching pov block

* fix runtime compilation

* all tests build

* fix some grumbles

* Update validation/src/collation.rs

Co-Authored-By: rphmeier <rphmeier@gmail.com>

* Update primitives/src/parachain.rs

Co-Authored-By: rphmeier <rphmeier@gmail.com>

* Update network/src/lib.rs

Co-Authored-By: rphmeier <rphmeier@gmail.com>

polkadot/validation/src/attestation_service.rs

@@ -42,7 +42,7 @@ use tokio::runtime::TaskExecutor;
 use tokio::runtime::current_thread::Runtime as LocalRuntime;
 use tokio::timer::Interval;
 
-use super::{Network, Collators, TableRouter};
+use super::{Network, Collators};
 
 /// Gets a list of the candidates in a block.
 pub(crate) fn fetch_candidates<P: BlockBody<Block>>(client: &P, block: &BlockId)
@@ -117,7 +117,6 @@ pub(crate) fn start<C, N, P>(
 		P::Api: ParachainHost<Block> + Core<Block> + BlockBuilder<Block>,
 		N: Network + Send + Sync + 'static,
 		N::TableRouter: Send + 'static,
-		<<N::TableRouter as TableRouter>::FetchIncoming as IntoFuture>::Future: Send + 'static,
 		<N::BuildTableRouter as IntoFuture>::Future: Send + 'static,
 {
 	const TIMER_DELAY: Duration = Duration::from_secs(5);