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/support/src/lib.rs

@@ -36,7 +36,7 @@ extern crate mashup;
 #[cfg(test)]
 #[macro_use]
 extern crate pretty_assertions;
-#[cfg(test)]
+#[cfg(feature = "std")]
 #[macro_use]
 extern crate serde_derive;
 #[cfg(test)]
@@ -122,3 +122,6 @@ pub enum Void {}
 
 #[doc(hidden)]
 pub use mashup::*;
+
+#[cfg(feature = "std")]
+pub use serde_derive::*;