operations: make the motion blurs use angles from -180 to 180
operations: use "degree" not "degrees" as "unit" key value
operations: specify "axis" on pixelizes' ratio_x and ratio_y
operations: clean up properties of motion-blur-*
operations: some property fixes in mosaic and vignette
cubism: port to gegl-op.h
operations: make emboss always preserve alpha

also clean up the code and fix misleading use of "x" for the y-axis
and the other way around.
operations: always use "Random seed" not "Seed"
operations: rename noise.c to noise-perlin.c
operations: gegl:noise-cell -> gegl:cell-noise, like perlin and simplex
tests: gegl:noise-cell -> gegl:cell-noise
operations: "X Foo" -> "Foo X" for Foo in Offset, Size, Ratio, ...
property-keys: gegl_param_spec_set_property_key; remove return type
gegl-op: add macro based alternative to varargs property meta-data

Varargs in operation initialization can cause crashes on startup; that might
be masked by running on 32bit vs 64bit; and possibly other platform specific
traits.
noise-rgb: declare property (metadata) with macros instead of varargs
color: use macros instead of varargs for prop metadata
property meta data, add ui_steps to double and int

Add the ability to specify small and big step increments for properties in
GEGL augmented GParamSpecs for integers and doubles.
noise-rgb: experiment with macro based property meta-data
gegl-op, operations: get rid of gegl_ prefix for enum declaration
gegl-op: initialize default values for int/double