Interchain message-passing (#117)

* compute ingress and routing in polkadot runtime

* extract parent candidates from block when beginning consensus

* fetch incoming messages when validating

* fix consensus tests

* parachain wasm execution uses messages

* update parachain tests to check if messages are executed

* abstract out network service to make room for network tests

* skeleton for incoming data fetch

* collate ingress from consensus-gossip

* keep track of validated candidates in the shared-table

* add some shared_table tests for new behavior

* broadcast egress messages on gossip

* test compute_ingress

* move network tests to module folder

* dummy network for consensus-network tests

* make consensus network generic over executor

* test egress broadcast and ingress fetch

* fix test compilation

* address some grumbles

* address grumbles and fix parachain shuffle

* remove broadcast parameter from consensus network trait

polkadot/test-parachains/build.sh

@@ -2,7 +2,7 @@
 set -e
 
 # Make LLD produce a binary that imports memory from the outside environment.
-export RUSTFLAGS="-C link-arg=--import-memory,--export-table -C lto=fat -C panic=abort"
+export RUSTFLAGS="-C link-arg=--import-memory -C link-arg=--export-table -C panic=abort"
 
 for i in adder
 do