DS-2080 Cleanup bad/broken tests, and upgrade to latest JUnit and JMockit

**WARNING: THIS IS A WORK-IN-PROGRESS. DO NOT MERGE YET**

This Pull Request seeks to do the following:

1. Upgrade us to the latest JUnit (v4.11), JMockit (v1.10) and H2 database (v1.4.180).
2. Refactor `MockDatabaseManager` to no longer be an almost *complete* copy of `DatabaseManager`. Instead, only "mock" the methods we absolutely need to.
3. Fix many Unit Tests to use the latest JMockit syntax (esp. when using `NonStrictExpectations`)
4. Fix/cleanup Unit Tests which are broken or not independent (e.g. We have several "delete" tests which attempt to delete an object that is assumed to have been created by a different test. Unfortunately, if these tests run in the wrong order, failures will result as it will attempt to delete an item which does not exist.)