refactoring column part 1

src/mol-base/collections/_spec/column.spec.ts

src/mol-base/collections/column.1.ts

src/mol-base/collections/column.ts

src/mol-base/collections/integer/_spec/interval.spec.ts

src/mol-base/collections/integer/_spec/ordered-set.spec.ts

src/mol-base/collections/integer/_spec/segmentation.spec.ts

src/mol-base/collections/integer/_spec/sorted-array.spec.ts

src/mol-base/collections/integer/_spec/tuple.spec.ts

src/mol-base/collections/integer/segmentation.ts

src/mol-data/model.ts

src/mol-data/model/builders/mmcif.ts

src/mol-data/structure.ts

src/perf-tests/sets.ts