Change all action callbacks so they can be invoked by a GAction:
- add GimpActionCallback typedef:
void (* cb) (GimpAction*, GVariant*, gpointer)
- change all action callbacks to the GimpActionCallback signature
- add "gimp-activate" and "gimp-change-state" signals to GimpAction,
with the same signature as the resp. GAction signals
- remove all other custom action signals and only use the new
GimpAction signals
- pass around appropriate GVariants containing booleans, int32,
strings
- badly hack around to force a GimpProcedure pointer into a
uint64 variant
- remove all G_CALLBACK() casts from all action callbacks,
they all have the same signature now
Add property "color-tag" of type enum GimpColorTag to GimpItem so all
layers, channels and paths can be tagged with a color.
For interoperability, use the color list from Krita which is a
superset of Photoshop's colors.
Features a "Color Tag" submenu in the layers, channels and paths
menus, a row of color radio buttons in the properties dialogs,
undo and PDB API.
As a side effect, some common code is now factores out into
items-actions.[ch] and items-commands.[ch] which adds visible, linked
and lock actions for layers and channels.
Jehan