Remove unneeded Serde requirements (#1076)

* Remove superfluous serde requirements.

* Try to ensure hash is serde

* Fixups

* Building again

* Attempt to reenable Block (doesn't build)

* Fixes compilation for node cli

* Fixes test compilation

* Fix wasm

* Fix tests

* Remove unneeded changes

* Fix up comments

* Reenable some code

* Compile error when origin misused.

* Remove unnecessary includes of `serde_derive`

* Cleanups

substrate/srml/example/Cargo.toml

@@ -6,7 +6,6 @@ authors = ["Parity Technologies <admin@parity.io>"]
 [dependencies]
 hex-literal = "0.1.0"
 serde = { version = "1.0", default-features = false }
-serde_derive = { version = "1.0", optional = true }
 parity-codec = { version = "2.1", default-features = false }
 parity-codec-derive = { version = "2.1", default-features = false }
 substrate-primitives = { path = "../../core/primitives", default-features = false }
@@ -21,7 +20,6 @@ srml-balances = { path = "../balances", default-features = false }
 default = ["std"]
 std = [
 	"serde/std",
-	"serde_derive",
 	"parity-codec/std",
 	"parity-codec-derive/std",
 	"sr-std/std",

substrate/srml/example/src/lib.rs

@@ -34,13 +34,6 @@ extern crate substrate_primitives;
 // Needed for various traits. In our case, `OnFinalise`.
 extern crate sr_primitives;
 
-// Needed for deriving `Serialize` and `Deserialize` for various types.
-// We only implement the serde traits for std builds - they're unneeded
-// in the wasm runtime.
-#[cfg(feature = "std")]
-#[macro_use]
-extern crate serde_derive;
-
 // Needed for deriving `Encode` and `Decode` for `RawEvent`.
 #[macro_use]
 extern crate parity_codec_derive;