Extended Balance Type for Staking's Election (#2134)

* First draft of extended balance type

* Test cleanup.

* Update staking docs.

* Add a good failing test case for quintill

* Bring back saturating.

* Some final fixes

* A few more.

* Update wasm; Bump spec;

* Re-bump.

* Custom lossy conversion from currency to vote

* remove print

* Fix reverse conversion issue.

* void. Re-trigger ci.

substrate/node/runtime/src/lib.rs

@@ -34,7 +34,7 @@ use client::{
 use runtime_primitives::{ApplyResult, generic, create_runtime_str};
 use runtime_primitives::transaction_validity::TransactionValidity;
 use runtime_primitives::traits::{
-	BlakeTwo256, Block as BlockT, DigestFor, NumberFor, StaticLookup,
+	BlakeTwo256, Block as BlockT, DigestFor, NumberFor, StaticLookup, CurrencyToVoteHandler
 };
 use version::RuntimeVersion;
 use council::{motions as council_motions, voting as council_voting};
@@ -58,8 +58,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node"),
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
-	spec_version: 51,
-	impl_version: 51,
+	spec_version: 52,
+	impl_version: 52,
 	apis: RUNTIME_API_VERSIONS,
 };
 
@@ -129,6 +129,7 @@ impl session::Trait for Runtime {
 
 impl staking::Trait for Runtime {
 	type Currency = balances::Module<Self>;
+	type CurrencyToVote = CurrencyToVoteHandler;
 	type OnRewardMinted = Treasury;
 	type Event = Event;
 	type Slash = ();