Adding after response interceptors and exposing resource instance context to before response interceptors

Added the ability to add after response interceptors that can perform extra actions on the actual resource instance in the case of create/update/delete.

Added a new context property for before response interceptors so they have access to the calling resource instance in the case of create/update/delete.  This should expose enough information to address #45 using a custom beforeResponse callback or responseInterceptor.