Introduce safe types for handling imbalances (#2048)

* Be a little safer with total issuance.

* PairT instead of _Pair

* Remove rev causing upset

* Remove fees stuff.

* Fix build (including tests)

* Update runtime, bump version

* Fix

* Handle gas refunds properly.

* Rename identifier

ala #2025

* Address grumbles

* New not-quite-linear-typing API

* Slimmer API

* More linear-type test fixes

* Fix tests

* Tidy

* Fix some grumbles

* Keep unchecked functions private

* Remove another less-than-safe currency function and ensure that
contracts module can never create cash.

* Address a few grumbles and fix tests

substrate/node/runtime/wasm/Cargo.lock

@@ -801,7 +801,6 @@ dependencies = [
  "srml-council 0.1.0",
  "srml-democracy 0.1.0",
  "srml-executive 0.1.0",
- "srml-fees 0.1.0",
  "srml-finality-tracker 0.1.0",
  "srml-grandpa 0.1.0",
  "srml-indices 0.1.0",
@@ -1295,6 +1294,23 @@ dependencies = [
  "subtle 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "schnorrkel"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "clear_on_drop 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "curve25519-dalek 1.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ed25519-dalek 1.0.0-pre.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "merlin 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_chacha 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sha3 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "subtle 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "scopeguard"
 version = "0.3.3"
@@ -1563,7 +1579,6 @@ dependencies = [
  "sr-sandbox 0.1.0",
  "sr-std 0.1.0",
  "srml-balances 0.1.0",
- "srml-fees 0.1.0",
  "srml-support 0.1.0",
  "srml-system 0.1.0",
  "srml-timestamp 0.1.0",
@@ -1616,22 +1631,6 @@ dependencies = [
  "srml-system 0.1.0",
 ]
 
-[[package]]
-name = "srml-fees"
-version = "0.1.0"
-dependencies = [
- "hex-literal 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 3.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec-derive 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
- "sr-io 0.1.0",
- "sr-primitives 0.1.0",
- "sr-std 0.1.0",
- "srml-support 0.1.0",
- "srml-system 0.1.0",
- "substrate-primitives 0.1.0",
-]
-
 [[package]]
 name = "srml-finality-tracker"
 version = "0.1.0"
@@ -2010,7 +2009,7 @@ dependencies = [
  "regex 1.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "ring 0.14.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "schnorrkel 0.0.0 (git+https://github.com/w3f/schnorrkel)",
+ "schnorrkel 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2643,6 +2642,7 @@ dependencies = [
 "checksum ryu 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "eb9e9b8cde282a9fe6a42dd4681319bfb63f121b8a8ee9439c6f4107e58a46f7"
 "checksum safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7f7bf422d23a88c16d5090d455f182bc99c60af4df6a345c63428acf5129e347"
 "checksum schnorrkel 0.0.0 (git+https://github.com/w3f/schnorrkel)" = "<none>"
+"checksum schnorrkel 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a700659388785588c75b197cecda0f23c7112a9281ef703e8ffc651061ce014c"
 "checksum scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "94258f53601af11e6a49f722422f6e3425c52b06245a5cf9bc09908b174f5e27"
 "checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
 "checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"