v2.18.0

Spotymod 2.18.0

New faceplate: the panel reads its captions from a table instead of
baking them into the plate, so every caption tells the truth about the
engine that is selected. MELODY does one thing per engine, REC appears
only where it records, and the RATE/TIME/ROOM/PITCH wording is now
DIV/MULT/SEND/BEND.

Reverb and master:
- SMEAR glides the diffuser LFOs instead of stepping them -- the
  bit-reduction artefacts at high SMEAR are gone.
- The top tenth of DECAY is playable instead of dead, and the bloom now
  leaves headroom at the master sum.
- The master DRIVE curve is square, so its action spreads over the whole
  travel rather than its first fifth.

NOTE: two remaps. Saved DRIVE values shift (0.5 was 2.5x, now 1.75x),
and so do DECAY values between 0.9 and 1.0 (0.95 was loop gain 1.05,
now 1.025). Patches touching those ranges will sound different.