gegl: Update to 0.4.24

Changelog:
GEGL-0.4.24 2020-06-07

Build:
~~~~~~

CI creation and caching of container images for build.  Force support for 64bit
file offsets on win32, re-enabling >2GB tile swap, fallout from migration to
meson. Operations in workshop are now built as a bundle.

Core:
~~~~~

cppcheck liniting fixes. Report pixel-formats as part of graphviz debug.  New
meta-data API, that permit handling non-exif metadata in different file loaders
and savers in a generic manner. Use g_ascii_strtod to avoid being tripped up
by ',' expected through locale.

Buffer:
~~~~~~~

Fixed integer overflow in u32 bilinear blit scaler.

Changed cubic interpolation to be a bit softer, reducing induced moire seen in
issue #167. Speeded up cubic sampler with custom inlinable fabsf.

Gracefully fail when running out of swap space. issue #229 Avoid
possible deadlock in file monitoring, working around upstream issue.  Reduced
contention on tile allocation. Allow creating buffers with uninitialized data,
and tracking of empty tiles in tile backends. Sleep on tile lock contention,
reducing contention when hyperthreading. Cppcheck liniting fixes.

Operations:
~~~~~~~~~~~

Meta-operations now have an additional vfunc, update(), which gets invoked on
property changes, all meta ops have been refactored to use the new cleaner API.
gegl_operation_meta_watch_node(s) were already effectively nops, they are
marked as deprecated and left as stubs for thid party ops still calling them.

We now provide our own inlined versions of some basic single precision floats
ops, this enables inlining of performance critical code also with lower
optimization levels.

crop: with no parameters set, infer rectangle to crop from graph.

crop: cropping rectangle can be implied from graph.
hue-chroma: avoid modifying hue/chroma of neutrals
dropshadow: added option for shadow growing
median-blur: accept negative radius values
rgb-clip: add parameters for specifying clipping ranges
vignette: new shapes, horizontal and vertical.
imgcmp: make max-diff property conform to gobject standard.
save-pixbuf: use a GObject for consumer read instead of pointer property.
gegl-graph: add a gegl-chain tutorial as default script.

New Ops:

border-align: place a buffer within the borders of another one.
pack: joins two buffers into one, with optional gap.
bloom: adds a glow around highlights.
piecewise-blend: uses a grayscale map as index into array of buffers used as LUT.
variable-blur: uses piecewise-blend piecewise-blend and gaussian blur to approximate blurs with per-pixel blur radius.
focus-blur: a vignetting blur, using variable-blur.
reset-origin: moves upper left of extent to 0,0
band-tune: parametric band equalizer for tuning frequency bands of image.


(ryoon)