Remove use of Snak class alias

Change-Id: I99d61568d77581c45c0d67cb0ff29fdff4f77e1e
Use temp fork of WikibaseDataModel

Change-Id: I3c577796ad4fe32ebcb5f0c8e6fdbb6752300576
Run tests in debug mode
Eliminate use of EntityId class alias

Change-Id: Icd7adeb6d0d13fbf9716cb2e409dea9f7067c06d