wip, refactoring

src/apps/render-test/components/viewport.tsx

src/apps/render-test/state.ts

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

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

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

src/mol-gl/renderer.ts

src/mol-gl/scene.ts

src/mol-util/input/input-observer.ts

src/mol-view/camera/base.ts

src/mol-view/camera/orthographic.ts

src/mol-view/camera/perspective.ts

src/mol-view/camera/util.ts

src/mol-view/controls/trackball.ts

src/mol-view/util.ts

src/mol-view/viewer.ts