Add code to delete existing records for a id when we try to add the id to the index_event table.
add simple test for the IndexEventDAO class -- adding, removing, listing events in the DB table. https://projects.ecoinformatics.org/ecoinfo/issues/5944
upgrade to Metacat 2.1.0 on the trunk. This includes a new index_event table for storing indexing events that need to be reprocessed. https://projects.ecoinformatics.org/ecoinfo/issues/5944