Add clear() method to storage interface and drivers.
Check calls both to driver and to callback in storage tests.
Merge pull request #72 from leftclickben/ClearRepositoryMethod

Add clear() method to storage interface and drivers.
Basic working mechanism for passing model methods to repositories.
Simplify code in get()
Description change only
Cleanup of storage unit test.
Merge pull request #73 from leftclickben/Models

Models
Version bump 0.0.4