Draw it!

- Ready motions no longer make a block glow by themselves: "Glows" is off unless you turn it on (or the texture
  already glows, and then it can be turned off).
- Fixed: one brush stroke in 3D over several parts of a texture (the chest and legs of armour, the top and side of a
  block) took several undos; now it is one.
- Ready motions stack: click several (a pulse and sparkles, a lamp and a glint); click one again to take it off.
  Motions of different lengths fit into one loop by themselves (up to 64 frames).
- "On layer": each motion goes on every layer or on one layer only, so a lamp's frame stays still while its light
  pulses.
- "Over its frames": a texture that already moves (an earlier motion, water, magma) keeps its frames under new
  motions, so they can be added in several goes.
- New motions: Rise (fire, bubbles), Slide (a running belt), Wave (a flag, weed in water), Fade (a layer fading out
  and back in).
- "Glows" lights up only the layers that move.