Formatting alignment
PagedEnumerator

This will allow us to query a paginated API response from the
convenience of the `#each` method. This will only require the
initial response, and a block that describes how the items on the
page should be enumerated, and how the next page should be retrieved.
Base class for shared API functionality

Any API that is created will need a reference to the client. So far,
that is the only common functionality that needs to be shared.
Order API

Adds an API to retrieve orders from an Ecwid store.