Add additional tests

[mucaho]

Add additional tests to improve test coverage:

• investigate if old incoming messages (> 2 min) get dropped correctly, check for their difference with current ids (dataId & transmissionId), if id_diff > RANGE / 4 then drop & test that
• investigate if there is an off-by-1 error when reaching max retransmit MetaDatas in packet & test that
• add tests for Controller (data & packet as input)
• test ReceivedMapControl.removeEntry as its not trivial
• implement SimpleMapControlTest.testDiscardTimedoutEntries & SimpleMapControlTest.testDiscardEntryTooOften
• add int to long test to PrimitiveValuesTest
• check if pendingMapSize & receivedMapSize is empty in DelayedTest
• test empty retransmits (unidirectional communication)
• although Protocol's methods are synchronized, the returned collections are not and could be modified in between method calls, test this
• extend WanEmulator to simulate lag spikes where every packet gets dropped for a period of time