State machine crate and rust impl of executor (#17)

* Executor.

* Rust contracts implementation.

* Add documentation and fix transfer data.

* Fix auth contract interface.

* Add some executor tests.

* Validator set contract.

substrate/contracts/src/lib.rs

@@ -0,0 +1,47 @@
+// Copyright 2017 Parity Technologies (UK) Ltd.
+// This file is part of Polkadot.
+
+// Polkadot is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Polkadot is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Temporary crate for contracts implementations.
+//!
+//! This will be replaced with WASM contracts stored on-chain.
+
+#![warn(missing_docs)]
+
+extern crate polkadot_primitives as primitives;
+extern crate polkadot_serializer as serializer;
+extern crate polkadot_state_machine as state_machine;
+extern crate serde;
+
+#[macro_use]
+extern crate error_chain;
+#[macro_use]
+extern crate serde_derive;
+
+#[cfg(test)]
+#[macro_use]
+extern crate assert_matches;
+
+mod auth;
+mod balances;
+mod validator_set;
+
+pub mod error;
+pub mod executor;
+
+/// Creates new RustExecutor for contracts.
+pub fn new() -> executor::RustExecutor {
+	executor::RustExecutor::default()
+}