D-Net

#1257 renaming 'eu.dnetlib.iis.avro.map.output.value.class' property (which become obsolete) required by CollapserReducer to 'collapser.reducer.schema.class'.

#577 renaming origins to matched and ingested

#577 fixing PMC citations collapser by executing toString() on text when retrieving map value

#577 introducing PMC citations collapser