Parse sec struct from mmCIF

src/apps/structure-info/model.ts

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

...odel/structure/model/formats/mmcif/secondary-structure.ts

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

...ol-model/structure/model/properties/seconday-structure.ts

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

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

src/mol-util/bit-flags.ts