v0.47.0 — the 9/7 synthesis stops moving data it already had

Faster on the heaviest pages, byte-identical output

Takes go-images/jpeg2000 v0.7.0, which folds two redundant passes out of the
9/7 vertical wavelet synthesis — the inverse scaling into the subband read-out,
and the interleave into the scatter. Neither changes an arithmetic operation.

min-of-5, two interleaved rounds, against a ±1% noise floor:

document	before	after
b31820797.pdf	786.3 ms	721.2 ms	−7.7%
bulletinchicagov48nchicg.pdf	657.7 ms	636.7 ms	−4.4%
irrigationrequir1340fort.pdf	404.7 ms	388.5 ms	−3.4%

All 3 215 corpus documents render byte-identical to v0.46.0.

Also carries go-highway v0.0.12 and opentype v0.13.0, taken in v0.46.0's
wake: nothing was updating this repository's dependencies, and go-highway had
been eight released versions behind.