Some event records can lead to a crash

Some event records (e.g., CallConstructorEvents), namely all records that implement IFlowRecord but extend neither AfterOperationEvent nor BeforeOperationEvent, can lead to a crash within the tool. Although they are simply ignored by the Trace Diagnosis Tool (they could be added to the dangling records from Issue #7 (closed) by the way), the filter thinks that the trace is complete, when the first event of the trace is one of these records.