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.