* change logging to metrics and add section on Engine
* add to the migration guide
* address feedback and add clarity around logFunction
* address feedback for migration guide
* 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
* Enable declarationMap in tsconfig.json
See http://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-9.html
* Add apollo-server-caching package and improve typings
* Remove superfluous test steps
* Add .npmignore to apollo-server-caching
* Add apollo-server-env and apollo-datasource-rest packages
* Fix broken imports
* Use prepublish instead of prepare
* cache is now passed to data sources from ApolloServer constructor
* fix Object.values to use the object passed in rather than this
* add initial datasource test
* docs: initial data source documentation
* docs: initial data source documentation
* compiles and documentation now highlights code in data-sources.md
* Some changes to the data source docs
* Add BadUserInputError and TransientError as extensions of ApolloError
* remove TransientError
* update test so that properties end up under `error.extensions.exception`
* update documentation to talk about BadUserInputError
* check for properties after formatApolloErrors has been called
* fixed highlighted lines for docs
* export BadUserInputError from `apollo-server`
* fixed highlighted lines for docs
* export BadUserInputError from `apollo-server`
* update changelog
