Merge pull request #1 from ObjectiveHAL/develop

OHResource now uses curies when evaluating embedded resources.
Merge pull request #2 from ObjectiveHAL/develop

Adopts NSCoding protocol for the OHLink class.
Merge pull request #4 from ObjectiveHAL/develop

Improvement to how background operations are performed.
Merge pull request #5 from ObjectiveHAL/develop

Cleans up use of NSOperation. Reliably calls completion handler now.
Merge pull request #6 from ObjectiveHAL/develop

Exposes NSOperation-based traversal. Enables more complex interactions.
Merge pull request #7 from ObjectiveHAL/develop

Fixes crash when completion handler is nil.
Merge pull request #8 from ObjectiveHAL/develop

Simplifications to how clients interact with ObjectiveHAL
Adds block-based retrieval of root resource.