Added ExportData class.  Use ExportData class instead of passing...

individual parameters for calls to "createDataExportTasks".  This is to fix a problem where the korsakow-js-player-plugin was needing new parameters for Maps, and this would create an ongoing (and with minimal changes, unnecessary) management problem when adding new capabilities that need export (like Maps).  By abstracting the data into a known class, we can avoid problems by using instances of the class for passing through the exporter.