improve surface bounding-sphere

CHANGELOG.md

src/mol-math/geometry/common.ts

src/mol-math/geometry/gaussian-density.ts

src/mol-math/geometry/gaussian-density/cpu.ts

src/mol-math/geometry/gaussian-density/gpu.ts

src/mol-math/geometry/molecular-surface.ts

src/mol-repr/structure/visual/gaussian-density-volume.ts

src/mol-repr/structure/visual/gaussian-surface-mesh.ts

src/mol-repr/structure/visual/gaussian-surface-wireframe.ts

src/mol-repr/structure/visual/molecular-surface-mesh.ts

src/mol-repr/structure/visual/molecular-surface-wireframe.ts

src/mol-repr/structure/visual/util/common.ts