message: use structure.uniqueResidues, removed duplicated code
diff: /**
  - * Copyright (c) 2017-2018 Mol* contributors, licensed under MIT, See LICENSE file for more info.
  + * Copyright (c) 2017-2019 Mol* contributors, licensed under MIT, See LICENSE file for more info.
  *
  * @author David Sehnal <david.sehnal@gmail.com>
  * @author Alexander Rose <alexander.rose@weirdbyte.de>
  @@ -9,8 +9,6 @@ import { Model } from '../../../../mol-model/structure/model/model'
  import { LinkType } from '../../../../mol-model/structure/model/types'
  import { CustomPropertyDescriptor } from '../../../../mol-model/structure';
  import { mmCIF_Database } from '../../../../mol-io/reader/cif/schema/mmcif';
  -import { Structure, Unit, StructureProperties, StructureElement } from '../../../../mol-model/structure';
  -import { Segmentation } from '../../../../mol-data/int';
  import { CifWriter } from '../../../../mol-io/writer/cif'
  export interface ComponentBond {
  @@ -29,7 +27,7 @@ export namespace ComponentBond {
  const chem_comp_bond = getChemCompBond(ctx.structures[0].model);
  if (!chem_comp_bond) return CifWriter.Category.Empty;
  - const comp_names = getUniqueResidueNames(ctx.structures[0]);
  + const comp_names = ctx.structures[0].uniqueResidueNames;
  const { comp_id, _rowCount } = chem_comp_bond;
  const indices: number[] = [];
  for (let i = 0; i < _rowCount; i++) {
  @@ -144,21 +142,4 @@ export namespace ComponentBond {
  model._staticPropertyData[PropName] = chemComp;
  return chemComp;
  }
  -
  - function getUniqueResidueNames(s: Structure) {
  - const prop = StructureProperties.residue.label_comp_id;
  - const names = new Set<string>();
  - const loc = StructureElement.Location.create();
  - for (const unit of s.units) {
  - if (!Unit.isAtomic(unit)) continue;
  - const residues = Segmentation.transientSegments(unit.model.atomicHierarchy.residueAtomSegments, unit.elements);
  - loc.unit = unit;
  - while (residues.hasNext) {
  - const seg = residues.move();
  - loc.element = unit.elements[seg.start];
  - names.add(prop(loc));
  - }
  - }
  - return names;
  - }
  }
  \ No newline at end of file
  