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/polkadot/runtime/src/environment.rs

@@ -17,7 +17,6 @@
 //! Environment API: Allows certain information to be accessed throughout the runtime.
 
 use rstd::boxed::Box;
-use rstd::mem;
 use rstd::cell::RefCell;
 use rstd::rc::Rc;
 
@@ -32,6 +31,8 @@ pub struct Environment {
 	pub parent_hash: Hash,
 	/// The current block digest.
 	pub digest: Digest,
+	/// The current transaction index
+	pub transaction_index: u64,
 }
 
 /// Do something with the environment and return its value. Keep the function short.
@@ -52,7 +53,7 @@ fn env() -> Rc<RefCell<Environment>> {
 			let singleton: Rc<RefCell<Environment>> = Rc::new(RefCell::new(Default::default()));
 
 			// Put it in the heap so it can outlive this call
-			SINGLETON = mem::transmute(Box::new(singleton));
+			SINGLETON = Box::into_raw(Box::new(singleton)) as *const _;
 		}
 
 		// Now we give out a copy of the data that is safe to use concurrently.
@@ -73,7 +74,7 @@ fn env() -> Rc<RefCell<Environment>> {
 			let singleton: Rc<RefCell<Environment>> = Rc::new(RefCell::new(Default::default()));
 
 			// Put it in the heap so it can outlive this call
-			*s.borrow_mut() = mem::transmute(Box::new(singleton));
+			*s.borrow_mut() = Box::into_raw(Box::new(singleton)) as *const _;
 		}
 
 		// Now we give out a copy of the data that is safe to use concurrently.