Fix for Issue #98.

When breaking the synthesis machine, its "ghost" inventory is dumped into the world along with real inventory. This allows for duping, as per issue #98. This set of changes cleans up the breakBlock methods for all BlockMinechemContainer classes so they use a single routine in the base class, with the existing specialized inventory-filtering methods in each subclass (addStacksDroppedOnBlockBreak). It also adds unit tests for drops for the base class and for the synthesizer block, to help catch any inventory-related regressions. The unit tests require PowerMock+EasyMock and JUnit4 to run.