Variopinta 0.6.0

Variopinta 0.6.0

• Rename target configuration to input_spec and output_specs, require names
  for public targets and output ports, and give explicit targets a default
  ReturnArray(name="array") output.
• Make secondary pipeline, target, output, I/O, and transform configuration
  keyword-only. Rename PNG compression to compression_level.
• Replace sampled scalar shorthands with explicit *_range tuples, clarify
  affine and crop units, and add explicit pixel/fraction units to
  CoarseDropout hole sizes.
• Construct compiled pipelines and result containers through pipeline methods
  only. Pickles remain same-release artifacts; pickles from releases with the
  earlier field names are not supported.

Migration mappings for this breaking pre-1.0 release:

Earlier spelling	Current spelling
Image(carrier=..., outputs=..., name=...)	Image(input_spec=..., name=..., output_specs=...)
Encode(..., compression=n)	Encode(..., name=..., compression_level=n)
RandomResizedCrop(..., scale=..., ratio=...)	RandomResizedCrop(..., area_range=..., aspect_ratio_range=...)
Affine(degrees=d, translate=..., scale=s, shear=...)	Affine(degrees_range=(-d, d), translate_max_fraction=..., scale_range=(s, s), shear_x_range=..., shear_y_range=...)
GaussianNoise(mean=m, std=s)	GaussianNoise(mean_range=(m, m), std_range=(s, s))
Sharpen(alpha=a, lightness=s)	Sharpen(blend_weight_range=(a, a), strength_range=(s, s))

Convert every other sampled scalar to an explicit two-endpoint range. For old
ColorJitter scalar amounts, use the already-canonical factor endpoints:
brightness=0.2 becomes brightness_range=(0.8, 1.2). Add
hole_height_unit="pixels" or hole_width_unit="pixels" when migrating old
integer dropout ranges; omitted units mean fractions.