picking improvements

src/mol-canvas3d/canvas3d.ts

src/mol-canvas3d/helper/bounding-sphere-helper.ts

src/mol-canvas3d/helper/interaction-events.ts

src/mol-canvas3d/passes/pick.ts

src/mol-geo/geometry/base.ts

src/mol-geo/geometry/picking.ts

src/mol-gl/_spec/renderer.spec.ts

src/mol-gl/renderable.ts

src/mol-gl/renderer.ts

src/mol-plugin-state/manager/interactivity.ts

src/mol-repr/representation.ts

src/mol-repr/shape/representation.ts

src/mol-repr/structure/complex-visual.ts

src/mol-repr/structure/units-visual.ts

src/mol-repr/visual.ts

src/mol-repr/volume/representation.ts

src/tests/browser/render-shape.ts

src/tests/browser/render-structure.ts