0.17

• Data Matrix: new symbol_shape option ("square" default,
  "rectangular", "auto", also --symbol-shape in the CLI) adds the
  six rectangular ECC-200 sizes; "auto" picks the smallest-area symbol.
• Substantial performance improvements across all four 2D symbologies.
  Compared to 0.16 on a realistic payload corpus: typically ~2.7× faster for
  QR Code, ~2.2× for PDF417, ~1.3× for Data Matrix (rising to ~2.1× on large
  payloads), and ~4.7× for Aztec Code — where large payloads, which
  previously scaled poorly, are up to ~200× faster.
• QR Code: the frame, module-placement, mask and error-correction-block data
  is now constructed at encode time instead of being shipped as 200
  pre-computed data files, shrinking the installed package by about 6 MB.
• PDF417: automatic column selection now minimises physical symbol area
  within a scanner-friendly aspect band instead of targeting a square
  symbol, producing markedly smaller, wider symbols for small and medium
  payloads.