instead of passing N_()-strings; and remove gettext() calls on these
strings when using them. Reduces complexitx, and fixes double- and
untranslated strings. Also enables to treat properties of GIMP and
GEGL objects the same way, which was totally broken before.
It was misnamed from the beginning and has no relation to GimpImageMap
except that it happens to be used by GimpImageMapTools. Now it feels
less weird to potentially use it for other settings too.
and gimp-levels-tool.settings
Serialize the channel properties manually (not using
gimp_config_serialize_properties()), so the parent class' "time"
property doesn't end up in the config file once per channel.
