Serialisable genesis config (#229)

* Genesis serialization

* Custom type for AuthorityId

* Merge w master

* Fixed a few minor issues

* Fixed unmerged file

* Renamed tag

* Deferred genesis loading

* Upated wasm runtime

* Minor issues

substrate/demo/executor/src/lib.rs

@@ -207,7 +207,7 @@ mod tests {
 			democracy: Some(Default::default()),
 			council: Some(Default::default()),
 			timestamp: Some(Default::default()),
-		}.build_storage()
+		}.build_storage().unwrap()
 	}
 
 	fn construct_block(number: BlockNumber, parent_hash: Hash, state_root: Hash, extrinsics: Vec<BareExtrinsic>) -> (Vec<u8>, Hash) {