Proposal creation and evaluation to plug into BFT (#77)

* reshuffle consensus libraries

* polkadot-useful type definitions for statement table

* begin BftService

* primary selection logic

* bft service implementation without I/O

* extract out `BlockImport` trait

* allow bft primitives to compile on wasm

* Block builder (substrate)

* take polkadot-consensus down to the core.

* test for preemption

* fix test build

* Fix wasm build

* Bulid on any block

* Test for block builder.

* Block import tests for client.

* Tidy ups

* clean up block builder instantiation

* justification verification logic

* JustifiedHeader and import

* Propert block generation for tests

* network and tablerouter trait

* use statement import to drive creation of further statements

* Fixed rpc tests

* custom error type for consensus

* create proposer

* asynchronous proposal evaluation

* inherent transactions in polkadot runtime

* fix tests to match real polkadot block constraints

* implicitly generate inherent functions

* add inherent transaction functionality to block body

* block builder logic for polkadot

* some tests for the polkadot API

substrate/Cargo.lock

@@ -967,6 +967,7 @@ dependencies = [
  "polkadot-runtime 0.1.0",
  "substrate-client 0.1.0",
  "substrate-executor 0.1.0",
+ "substrate-keyring 0.1.0",
  "substrate-state-machine 0.1.0",
 ]
 
@@ -1007,8 +1008,11 @@ name = "polkadot-consensus"
 version = "0.1.0"
 dependencies = [
  "ed25519 0.1.0",
+ "error-chain 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "polkadot-api 0.1.0",
+ "polkadot-collator 0.1.0",
  "polkadot-primitives 0.1.0",
  "polkadot-statement-table 0.1.0",
  "substrate-bft 0.1.0",