Ensure Specification(June 2018) Compliance#631

Merged

LegNeato merged 14 commits intographql-rust:masterfrom

jmpunkt:graphql-spec-june-2018

May 2, 2020

Commits on Apr 24, 2020

Implemented most test cases from the specification
jmpunkt
committed

Commits on Apr 25, 2020

Unified error handling for all generators
jmpunkt
committed

Commits on Apr 26, 2020

Commits on Apr 29, 2020

Commits on May 1, 2020