Filled out more of MockDataStore

Filled in method stubs for the methods most likely to be used in MockDataStore.  Namely the save, simple retrieve, and the delete and deleteAll methods.  I think I have also determined how to get the Network, Request and DataStore mocks to interact correctly to simulate the networking, as Team Rolling Thunder's mock Network only simulates whether or not the request has been sent.  It does not actually simulate the entire process of sending a request using a controller.

I'll be adding that interaction later today if I can get it working.

Committed by: Alec Thompson - ajthompson