Add new string members to GimpImageMapTool and use them instead of the
resp. fields of GimpToolInfo. Change ::get_operation() to return the
operation name and a lot of strings for the UI, and create both the
GeglNode and the config object in GimpOperationTool. Lots of various
cleanups in GimpImageMapTool subclasses. This is an intermediate state
on the way of making the whole filter applying mechanism more generic
and less depending on subclasses.
Add "title" and "help_id" parameters and members/properties to
GimpToolDialog, GimpToolGui, GimpOperationTool. Also make the order of
parameters more consistent.
If the operation has an aux input, add a combo that allows feeding
it one of the image's channels. This is all work in progress and
and should allow to use any drawable of any image.
