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.
Apply and heavily modify patch from remyDev which adds "lock position"
to GimpItem, similar to "lock content". Lock position disables all
sorts of translation and transform, from the GUI and the PDB.
Cleaned up some aspects of the lock content code as well because a
second instance of similar code always shows what went wrong the first
time.
gimp-item-find-parasite -> gimp-item-get-parasite
gimp-item-list-parasites -> gimp-item-get-parasite-list
Also changed the signature of gimp-item-get-parasite-list's C wrapper
in libgimp to be sane.
and rename them yet again to be gimp_item_foo_parasite() instead of
gimp_item_parasite_foo() because the latter is just a misnaming (they
are not GimpItemParasites, they are GimpParasites attached to
GimpItems, just as layers are attached to images).
The item groups has all the duplicated functionality from drawable
and vectors (name, visible, linked etc).
Hijack the unused GIMP_PDB_REGION and turn it into GIMP_PDB_ITEM;
change all protocol aware files accordingly and bump the protocol
version number. Change script-fu to handle the new type.
