Simplified application by replacing AddElement and RemoveElement with single LogsAndSourcesElement.
Refactored ListEventLogsAndSources: Pulled out code that lists sources for a given log into new method ListSourcesForEventLog.
Refactored: Extracted common code at the start of each public method into new GetMachineNameDisplayText method.
Added new functionality: CheckEventLogsAndSources to check existence of event logs and sources.  Set display order for each method when it appears in the menu.
Renamed application from EventLogsCreateRemove to EventLogManager.  Updated assembly information.  Bumped assembly version to 1.3.0.0.
CheckEventLogsAndSources: When checking source, display the associated event log name if the source exists.