Second beta release of GraphQL-core 3.1, based on GraphQL.js v15.0.0rc2.
In addition to incorporating the latest changes in [GraphQL.js v15.0.0rc2](https://github.com/graphql/graphql-js/releases/tag/v15.0.0-rc.2), this release also contains the following improvements and changes:
* Following a [change in GraphQL.js](https://github.com/graphql/graphql-js/pull/2410) to keep the order of user provided types, the type map reducer for the GraphQLSchema has been removed.
* We now support inheritance when evaluating the `__typename` attribute (25).
* FieldNodes and InputValueNodes are now only DefinitionNodes, not TypeDefinitionNodes.
* The test suite now has 100% coverage, and less coverage will count as failure.
Contributors to this release were:
Cito, Hellzed
Thanks to everybody who contributed by sending bug reports or pull requests. Please continue to report any problems you find in this beta release, so that these can be fixed in the final v3.1 release.