EG/HM: new better leaves grouping
EG: smarter task grouping and in-thread merging
EG/HM: small refactorings
HM: New style indexSearcher with numberOfTasks; Moved executor to indexAndTaxonomhy
HM: Extracted into mergePool method
HM: Fixed mergePool call
HM: One poll; Merge that array
HM: 16 segments per tier
HM: Improved leaf_groups by skipping all empty groups