add timing mode

CHANGELOG.md

src/apps/viewer/app.ts

src/apps/viewer/index.html

src/extensions/alpha-orbitals/density.ts

src/extensions/alpha-orbitals/orbitals.ts

src/mol-canvas3d/canvas3d.ts

src/mol-canvas3d/passes/draw.ts

src/mol-canvas3d/passes/fxaa.ts

src/mol-canvas3d/passes/marking.ts

src/mol-canvas3d/passes/multi-sample.ts

src/mol-canvas3d/passes/pick.ts

src/mol-canvas3d/passes/postprocessing.ts

src/mol-canvas3d/passes/smaa.ts

src/mol-canvas3d/passes/wboit.ts

src/mol-geo/geometry/texture-mesh/color-smoothing.ts

src/mol-gl/compute/grid3d.ts

src/mol-gl/compute/histogram-pyramid/reduction.ts

src/mol-gl/compute/histogram-pyramid/sum.ts

src/mol-gl/compute/marching-cubes/active-voxels.ts

src/mol-gl/compute/marching-cubes/isosurface.ts