* core: return response object from runHttpQuery
* core: change gqlResponse to graphqlResponse and add custom RequestInit type
* core: add cache-control headers based on the calcualted maxAge
* core: add extensions check during cache-control header creation
* core: create headers when cacheControl is not enabled otherwise pass through extensions
* express: initial tests of CDN cach-contol headers
* core: fixed tests with applyMiddleware and pass cacheControl config
* core: cache hint fixes, ignore when no maxAge, and check for rootKeys
* core: check for hints of length 0
* core: node 10 fails file upload test for some stream reason
* docs: add cdn caching section to features
* add space after // in comments
* fix feedback: proxy alignment and response creation
Adds cache-control toggles for http header calculation and stripping out
the cache control extensions from the respose.
Brings the default calculation of headers in line with the proxy.
* fix links in comments
* fix tests with null dereference
* update cdn docs and migration guide to include latest cdn configuration
* add not for engine migration to set engine to false
* add engine set to false in migration guide
* express: fixed tests
* address feedback to use omit and documentation
* docs: cdn caching is alternative to full response caching
* add back epipe check in upload tests
ApolloServer builds in graphql-playground rather than graphiql, so we no longer
provide middleware for serving GraphiQL.
If this turns out to be an unpopular choice, we can always add support for
graphiql instead of graphql-playground back in later.
We prefer graphql-playground because it allows you to enter HTTP request
headers, view query history, and explicitly supports graphql@0.13.
