Introduce toy runtime for testing inside substrate. (#66)

* Introduce simple blockchain runtime for substrate tests.

* Remove bad files.

* Add needed wasm binaries.

* Refactoring.

- Repot files in test-runtime.
- Rename troublesome `Joiner::join` to `Joiner::and`.
- Rework `Slicable` to dedup code.

* More fixes and refactoring

* Rebuild substrate test wasm.

* Fix merge errors.

* Rename the disasterously named `to_vec` to `encode`.

Also rename `as_slice_then` to `with_encoded`.

* Tests for toy runtime.

* Fix doc nit

substrate/polkadot/runtime/src/lib.rs

@@ -19,28 +19,22 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 extern crate substrate_runtime_std as rstd;
+#[macro_use] extern crate substrate_runtime_io as runtime_io;
+extern crate substrate_runtime_support as runtime_support;
 
-#[macro_use]
-extern crate substrate_runtime_io as runtime_io;
-
-#[cfg(feature = "std")]
-extern crate rustc_hex;
+#[cfg(feature = "std")] extern crate rustc_hex;
 
 extern crate substrate_codec as codec;
-extern crate substrate_primitives;
+#[cfg(feature = "std")] #[macro_use] extern crate substrate_primitives as primitives;
 extern crate polkadot_primitives;
 
-#[cfg(test)]
-#[macro_use]
-extern crate hex_literal;
+#[cfg(test)] #[macro_use] extern crate hex_literal;
 
-#[macro_use]
-pub mod support;
+pub mod environment;
 pub mod runtime;
 pub mod api;
 
-#[cfg(feature = "std")]
-pub mod genesismap;
+#[cfg(feature = "std")] pub mod genesismap;
 
 /// Type definitions and helpers for transactions.
 pub mod transaction {
@@ -72,7 +66,7 @@ pub mod transaction {
 	///
 	/// On failure, return the transaction back.
 	pub fn check(tx: UncheckedTransaction) -> Result<CheckedTransaction, UncheckedTransaction> {
-		let msg = ::codec::Slicable::to_vec(&tx.transaction);
+		let msg = ::codec::Slicable::encode(&tx.transaction);
 		if ::runtime_io::ed25519_verify(&tx.signature.0, &msg, &tx.transaction.signed) {
 			Ok(CheckedTransaction(tx))
 		} else {