viewer tweaks, expose repr props

src/mol-app/ui/transform/ball-and-stick.tsx

src/mol-app/ui/transform/spacefill.tsx

src/mol-geo/representation/index.ts

src/mol-geo/representation/structure/ball-and-stick.ts

src/mol-geo/representation/structure/index.ts

...presentation/structure/visual/inter-unit-link-cylinder.ts

...presentation/structure/visual/intra-unit-link-cylinder.ts

src/mol-geo/representation/volume/index.ts

src/mol-util/index.ts

src/mol-view/stage.ts