wip, model/structure

src/mol-data/util/_spec/buckets.spec.ts

src/mol-data/util/buckets.ts

src/mol-model/structure/model/formats/mmcif.ts

src/mol-model/structure/model/formats/mmcif/sort.ts

src/mol-model/structure/model/model.ts

src/mol-model/structure/model/properties/atomic/hierarchy.ts

src/mol-model/structure/model/properties/coarse/hierarchy.ts

...mol-model/structure/model/properties/utils/atomic-keys.ts

...mol-model/structure/model/properties/utils/coarse-keys.ts

src/mol-model/structure/structure/element.ts