Fix Params deserialization on serde_json>=1.0.8 (#222)

* Fix Params deserialization on serde_json>=1.0.8

Due to serde-rs/json#389, serde_json no longer calls `deserialize_any` in `deserialize_identifer` (and all other default implemented methods). This causes `Params` to fail to deserialize maps and sequences since it has hinted that it expects an identifier.

This implements `deserialize` correctly, saying that it accepts any type.

* Fix Id deserialization on serde_json>=1.0.8

core/src/types/id.rs

@@ -29,7 +29,7 @@ impl Serialize for Id {
 impl<'a> Deserialize<'a> for Id {
 	fn deserialize<D>(deserializer: D) -> Result<Id, D::Error>
 	where D: Deserializer<'a> {
-		deserializer.deserialize_identifier(IdVisitor)
+		deserializer.deserialize_any(IdVisitor)
 	}
 }
 

core/src/types/params.rs

@@ -50,7 +50,7 @@ struct ParamsVisitor;
 impl<'a> Deserialize<'a> for Params {
 	fn deserialize<D>(deserializer: D) -> Result<Params, D::Error>
 	where D: Deserializer<'a> {
-		deserializer.deserialize_identifier(ParamsVisitor)
+		deserializer.deserialize_any(ParamsVisitor)
 	}
 }