implemented batch processor (#27)
integrated buffer and batch processor into SPARQL connector (#27)
changed batch processor implementation to combine INSERT statements (#27)
added tests (#27)
changed connector to buffer up to 50 triple inserts in batch mode (#27)
increased batch size (#27)
added test (#27)
changed batch processor to use INSERT INTO [...] SELECT [...] syntax (#27)
removed ID column as it is never referenced (#27)