Update GraphQL to latest version and add / improve support for passed arguments

[johannilsson]

Arguments sent to the GraphQL endpoint is sent as a string from GraphiQL and needs to be deserialized before they're passed to the GraphQL library. Other GraphQL implementations also seems to handle this case.

The GraphQL version OTP is currently on does not work with complex types sent as arguments, this has been fixed in newer versions of the library.

[barslett]

Does anyone of you guys @johannilsson or @hannesj know anything about GraphiQL (https://github.com/graphql/graphiql). One of our developers looked at it, and it could make it easier to develop against GraphQL.

[andreyz]

@barslett you might even like a native wrapper around it https://github.com/skevy/graphiql-app.

More great GraphQL resources here https://github.com/chentsulin/awesome-graphql

[hannesj]

@barslett We are using it at http://dev.hsl.fi/graphql/console/

Also the locally installable version for development.