added intersectionSize to interval, sorted-array, ordered-set

src/mol-data/int/_spec/interval.spec.ts

src/mol-data/int/_spec/ordered-set.spec.ts

src/mol-data/int/_spec/sorted-array.spec.ts

src/mol-data/int/impl/interval.ts

src/mol-data/int/impl/ordered-set.ts

src/mol-data/int/impl/sorted-array.ts

src/mol-data/int/interval.ts

src/mol-data/int/ordered-set.ts

src/mol-data/int/sorted-array.ts

src/mol-geo/representation/structure/visual/util/polymer.ts