* Replaces primary key with `RKEntityIdentifier`
* Add support for use of compound keys for object identification
* Refactor `RKConnectionMapping` to `RKConnectionDescription` and add support for connecting with multiple attributes
* Clarify naming of representation key methods to better match naming conventions
* Add type transformation support for object identification
* Greatly expand test coverage for object identification
* Drop the `NSEntityDescription` category
* Simplify the `RKManagedObjectCaching` protocol
* Add compound key support to the Fetch Request and In Memory Cache implementations
* Replace Kiwi with Specta for tests where contexts are helpful for organization
* Rename `defaultValueForMissingAttribute` to `defaultValueForAttribute`
* RKObjectParameterization now returns an empty dictionary if mapping produces an unmappable representation error (no mappable attributes/relationships found)
* Log errors if request construction results in an NSError and return nil
* Ensure errors are passed back up through object parameterization instead of just returning nil
* Reset the serialization MIME Type registry during RKTestFactory set up to ensure it is in a sane state
* Convert Hamcrest matchers to Expecta in the object mapper tests to fix infinite recursion on test failure (will need to completely phase out Hamcrest soon)
* Provides for the registration of route either by class and method or via symbolic name
* Changed routes representation from simple dictionary to RKRoute model
* Eliminated RKRouter as a protocol
* Migrated RKObjectRouter to Network layer and renamed to RKRouter
* Added router as property of RKClient, RKObjectManager now proxies access
set due to an unchanged value. Update RKMapperTest to correctly validate mappings that do not result
in a value change (typically nil => nil). closes#72, fixes#634
* Reorganized tests to accommodate split into Logic & Application.
* Eliminated 'Spec' naming in favor of 'Test' as the suite is entirely based on SenTest.
* Pulled majority of testing support classes up into the library and documented them.
* Introduced RKApplicationTests app for running the RKTableController UI tests
