* Fixed project setup
* Loading existing operations from CoreData
Added a method for saving operations and new tests.
* Added a fetch operation to the data store
* Added new tests
* Added a method for removing operations
* Added new tests
Renaming MKDataStore to MKOperationStore
Added a project for testing MKPersistentQueue
Updated the README file
Merge pull request #2 from marcinkuptel/feature/backing_store

New operation store method + tests