Verify that a type name is specified before overriding class's type name

[sburba]

Fixes #365 The schema actually gets the correct types, it's just the GraphQL facade that doesn't load them correctly. Which means GraphQL::type() doesn't work for types specified in the types array of a schema.

Although really only the second and later types fail because 0 coerces to false and is therefore ignored

[coveralls]

Coverage remained the same at 70.537% when pulling 98127dbade96fe4b7d01fe8757677a59178dc10f on sburba:develop into 171631a17e4bf33780513f15221ea6052c67d498 on Folkloreatelier:develop.

[sburba]

Looks like that build failure is 5.6 failing for an unrelated reason. It just timed out before doing anything as far as I can tell. I'm not sure how to kick it off again if that's what needs to be done