Basic-shopify-api

* Rate limiting for REST has been improved to use a moving window method
* `Sleep` deferrer now returns a float for the time microtime
* `Memory` store now has a `reset` method to support the new rate limiting
* `Memory` now accepts more then two values to support the new rate limiting

*Contains breaking changes*; Consult `UPGRADING.md`.

* Library refactored and split up, no longer one file
* Auth header handling moved into Guzzle middleware
* API versioning handler moved into Guzzle middleware
* Rate limiting improved and now available for GraphQL
* Options moved into its own configuration class
* "Retry" ability now built-in via `guzzle_retry_middleware` which respects Shopify's 'X-Retry-After' header
* API responses are now mapped into a response class which can be accessed as an array or object
* Storage of how/where rate limits, request times, and others are now changable with the `StateStorage` interface, and a default in-memory storage class provided
* Both GraphQL and REST success and error returns have been normalized

* Added `bodyArray` to response object of rest and graph, this is the same as `body` except instead of a stdClass being returned, its an array.

* Added response to error callback function (64)
* Allow for additional client creation options (65)

* Added return types to all functions.
* Added async support for GraphQL via `graphAsync`.
* Added support for call to `/admin/oauth/access_scopes.json`.

* Fix for REST calls not properly building error object (47).