* Removed text about source code
Source code was removed by hasura/graphql-engine@fb3794c3
* links update for subscriptions/index
links updated because
1) facebook.github.io was changed to graphql.github.io/graphql-spec/
2) path to docs changed by apollographql/apollo-client@41ca8ff1
Changes compared to `/v1alpha1/graphql`
* Changed all graphql responses in **/v1/graphql** endpoint to be 200. All graphql clients expect responses to be HTTP 200. Non-200 responses are considered transport layer errors.
* Errors in http and websocket layer are now consistent and have similar structure.
