Initial mechanics for 80:20 fee split (#2912)

* Initial mechanics for 80:20 fee split

Also:
- Introduce extra functions for Imbalance manipulation;
- Store treasury pot in an account, letting total issuance account for
  it.

* Fix some tests

* Fix some tests

* Minor cleanups

* Update parity-codec version (#2855)

* Update parity-codec version

* Update grandpa, rhododendron and trie-bench

* Use primitive-types from crates.io

* Bump impl version

* Fix trie-bench version

* Fix lock files

* Fix versions

* Update codec to 4.1

* merge fix

* Revert merge

* More reversions

* Remove accidental code

* Update locks

* Bump runtime

* Update locks

* Tweaks and label TODO

* Update srml/treasury/src/lib.rs

Co-Authored-By: DemiMarie-parity <48690212+DemiMarie-parity@users.noreply.github.com>

* Update issue number

* Update core/sr-primitives/src/traits.rs

Co-Authored-By: Robert Habermeier <rphmeier@gmail.com>

* Fix wasm build

* Fix subkey build

substrate/srml/authorship/src/lib.rs

@@ -18,6 +18,8 @@
 //!
 //! This tracks the current author of the block and recent uncles.
 
+#![cfg_attr(not(feature = "std"), no_std)]
+
 use rstd::prelude::*;
 use rstd::collections::btree_set::BTreeSet;
 use srml_support::{decl_module, decl_storage, for_each_tuple, StorageValue};
@@ -102,6 +104,15 @@ pub trait FilterUncle<Header, Author> {
 		-> Result<(Option<Author>, Self::Accumulator), &'static str>;
 }
 
+impl<H, A> FilterUncle<H, A> for () {
+	type Accumulator = ();
+	fn filter_uncle(_: &H, acc: Self::Accumulator)
+		-> Result<(Option<A>, Self::Accumulator), &'static str>
+	{
+		Ok((None, acc))
+	}
+}
+
 /// A filter on uncles which verifies seals and does no additional checks.
 /// This is well-suited to consensus modes such as PoW where the cost of
 /// equivocating is high.
@@ -201,8 +212,8 @@ decl_module! {
 
 		fn on_finalize() {
 			// ensure we never go to trie with these values.
-			let _ = <Self as Store>::Author::take();
-			let _ = <Self as Store>::DidSetUncles::take();
+			<Self as Store>::Author::kill();
+			<Self as Store>::DidSetUncles::kill();
 		}
 
 		/// Provide a set of uncles.