Slash Authorities for irrefutable misbehavior (#84)

* double-commit and prepare misbehavior

* get misbehavior on completion

* collect misbehavior on drop, not only on success

* kill unused transaction_index field

* add primitive misbehavior report type

* add misbehavior report transaction

* store prior session

* fix set_items

* basic checks for misbehavior reports

* crate for substrate bft misbehavior checking

* integrate misbehavior check crate

* fix comment

* new wasm binaries

* fix hash in test

* import misbehavior transactions into queue

* fix test build

* sign on digest and full proposal when proposing

* detect proposal misbehavior

* fix fallout

* restore balance/bondage types

polkadot/primitives/src/lib.rs

@@ -80,3 +80,9 @@ pub type Signature = primitives::hash::H512;
 
 /// A timestamp: seconds since the unix epoch.
 pub type Timestamp = u64;
+
+/// The balance of an account.
+pub type Balance = u64;
+
+/// The amount of bonding period left in an account. Measured in eras.
+pub type Bondage = u64;