Introduce `resourceLinkURL`
Ensure that default options can be overridden at the class level.

JSONAPISource can now be *extended* with default namespaces, hosts and 
headers. These options can still be overridden in the constructor.
Clarify primary vs related records in `deserialize`
Remove TODOs from console.log statements
Refactor JSONAPISource for JSON API compatibility.

* separate “patch” and “std” modes of operations
* break out individual transform methods
* make default settings configurable through constructor as well as
  overriding class definition
Throw OperationNotAllowed when transform can’t process operation.
Fill out transform implementations in JSONAPISource.

Ensure both “patch” and “std” modes have complete implementations.