v0.0.6

Fixes from a review of 0.0.3–0.0.5 (engine, plugin, tests and docs):

• A bus with Velocity (or another note-time source) on Glide Time or EG Time used the
  previous note's value; now the note's own (Key: the key played, not the one it glides from).
• EG Sync: a sequenced note a hair before a sync unit no longer restarts a few samples in (a
  click with Reset on); MPC starting or stopping re-bases the count instead of restarting.
• MPC's position ran a few samples ahead after every block whose start wasn't on the 8-sample control
  grid (bar-locked busses and EG Sync); now exact.
• A latched envelope now lets go when MPC stops and on all notes off (CC 123), not only on all
  sound off.
• Duo with a droning osc 2 plays as Mono: a second key no longer retriggers.
• Pitch Bend is a bus source: with Bend To Off the wheel does what a bus makes of it (the guide
  promised that; there was no such source).
• The bus rate text updates at once when its rate mode changes (Hi shows ×10).
• Units: a duplicated track no longer shares its original's unit (no two live instances are the
  same unit); a project saved before units is unit 1, the same on every load; the unit reaches the
  engine together with the values it came with.
• The programmable destinations stay within their documented ranges with two busses or the Key
  source on them; per-note Analog offsets follow the knob (0 is ideal at once, not from the next
  note); EG Time moving every step no longer calls libm; a zero rate in a hand-built patch can't make
  NaNs; reset() between control steps no longer counts samples twice.
• DEPTH has its own Control selector (MOD's list left open showed open there too).
• The device trace marks state saves and loads (getChunk, setChunk), to see whether MPC restores
  parameters after a project's state.
• Analog at 0 is 0.0.4's sound bit for bit on the x86 build and within float rounding (−120 dB) on
  the device's fast-math build (0.0.5's notes said "sample for sample" for both).
• Tests: 640 (from 596), tightened where a check could pass with its feature broken.