Display whether a particular check operation picked up changes in the last run statistics

It is currently not possible to tell whether a check operation registered changes outside of going through the EventBroker logs. This could be alleviated by simply adding a Changes Registered field in the Last Run Statistics.

Examples of when this may become an issue include:

1. The operation list executes too quickly for changes to be displayed.
2. The EventBroker operator is away from the computer while the operation list executes and no warnings/errors appear.