Candidate Agreement + Consensus (#29)

* candidate statement importing

* import votes on validity

* import availability votes

* candidate receipt type

* make table mod public

* test context for table

* add harness for tests

* some tests for misbehavior

* produce proposal from table

* count candidate issuance as implicit vote

* keep track of messages known by validators

* fix primitives compilation

* simple BFT agreement

* kill unused macro_use annotation

* tests for BFT agreement

* test for not concluding on different prepares

* return summary upon statement import

* accept bft agreement on proposal not locally submitted

* check justification set for BFT

* BFT rewrite: vote accumulator with tests

* squash some warnings

* a few more tests for the accumulator

* add sender to table's signed statement

* implement honest node strategy for BFT

* inex -> index

* import and broadcast lock proofs

* poll repeatedly when state changes

* don't broadcast advance vote immediately if locked

* do not check validity of locked candidate

* basic tests for the strategy

* remove unused context trait and fix warning

* address some review grumbles

* address some more review nits

* fix lock import logic and add a test

* fix spaces

* fix a couple more style grumbles

* more type-safe justifications

* rename Communication enum variants

* improve some panic guard proofs

* add trailing comma

substrate/Cargo.lock

@@ -1,13 +1,3 @@
-[root]
-name = "polkadot-validator"
-version = "0.1.0"
-dependencies = [
- "error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "polkadot-primitives 0.1.0",
- "polkadot-serializer 0.1.0",
- "serde 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "aho-corasick"
 version = "0.6.3"
@@ -612,6 +602,14 @@ dependencies = [
  "polkadot-cli 0.1.0",
 ]
 
+[[package]]
+name = "polkadot-candidate-agreement"
+version = "0.1.0"
+dependencies = [
+ "futures 0.1.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "polkadot-primitives 0.1.0",
+]
+
 [[package]]
 name = "polkadot-cli"
 version = "0.1.0"
@@ -714,6 +712,16 @@ dependencies = [
  "triehash 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "polkadot-validator"
+version = "0.1.0"
+dependencies = [
+ "error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "polkadot-primitives 0.1.0",
+ "polkadot-serializer 0.1.0",
+ "serde 1.0.19 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "pretty_assertions"
 version = "0.4.0"