Jun 2018 spec

Validation step for schema extensions github.com/graphql/graphql-spec/pull/454
RFC3 - Accepted
Add validation steps for schema extensions by IvanGoncharov · Pull Request #454 · graphql/graphql-spec
RFC3 - Accepted
IsInputType and IsOutputType spec algorithms github.com/graphql/graphql-spec/pull/462
RFC3 - Accepted
Input & Output type definition by leebyron · Pull Request #462 · graphql/graphql-spec
RFC3 - Accepted
Validate directive arguments github.com/graphql/graphql-spec/pull/463
RFC3 - Accepted
Ensure validation of directive arguments by leebyron · Pull Request #463 · graphql/graphql-spec
RFC3 - Accepted