This is the consequence of previous commit. Plug-ins' label and
documentation are now localized before sending these data to GIMP core.
In other words, we replace N_() macros with basic gettext calls.

Hence avoiding the stderr messages. These are going to be localized with
centrally installed catalogs "gimp*-std-plugins", "gimp*-script-fu" and
"gimp*-python".

We now handle core plug-in localizations differently and in particular,
with kind of a reverse logic:

- We don't consider "gimp*-std-plugins" to be the default catalog
  anymore. It made sense in the old world where we would consider the
  core plug-ins to be the most important and numerous ones. But we want
  to push a world where people are even more encouraged to develop their
  own plug-ins. These won't use the standard catalog anymore (because
  there are nearly no reasons that the strings are the same, it's only a
  confusing logic). So let's explicitly set the standard catalogs with
  DEFINE_STD_SET_I18N macro (which maps to a different catalog for
  script-fu plug-ins).
- Doing something similar for Python plug-ins which have again their own
  catalog.
- Getting rid of the INIT_I18N macro since now all the locale domain
  binding is done automatically by libgimp when using the set_i18n()
  method infrastructure.

As explained in previous commits, the _peek_ call is advantageous
because:
- It is less bug-prone as we don't have to handle freeing the string. In
  all the cases I changed, I even spotted at least 2 cases where we were
  leaking a string (in file-mng, `temp_file_name` is never freed; and we
  were also leaking in an error case of gfig).
- As a consequence of the previous point: simpler code with less lines.
- In local file cases, the _peek_ variant does not even need to allocate
  an additional string.
- In other case, if we query several times the path, it is allocated
  once and cached so it stays efficient.
- When possible, working on the GFile rather than on a path string may
  be more robust. For instance I changed one g_unlink() into a
  g_file_delete(). Actually most reading/writing should be done with the
  GIO API when possible, but I didn't want to change too much code
  logics on this commit.

Orientation is now handled by core code, just next to profile conversion
handling.

One of the first consequence is that we don't need to have a non-GUI
version gimp_image_metadata_load_finish_batch() in libgimp, next to a
GUI version of the gimp_image_metadata_load_finish() function in
libgimpui. This makes for simpler API.
Also a plug-in which wishes to get access to the rotation dialog
provided by GIMP without loading ligimpui/GTK+ (for whatever reason)
will still have the feature.

The main advantage is that the "Don't ask me again" feature is now
handled by a settings in `Preferences > Image Import & Export` as the
"Metadata rotation policy". Until now it was saved as a global parasite,
which made it virtually non-editable once you checked it once (no easy
way to edit parasites except by scripts). So say you refused the
rotation once while checking "Don't ask again", and GIMP will forever
discard the rotation metadata without givin...

and in an attack of madness, changes almost all file plug-in
code to use GFile instead of filenames, which means passing
the GFile down to the bottom and get its filename at the very
end where it's actually needed.

to be GIMP_PDB_PROC_TYPE_PLUGIN, _EXTENSION etc.

If the comment doesn't UTF-8 validate, leave valid UTF-8 at the
beginning intact. Also fix character range comparison to use guchar
instead of gchar

Use gimp_image_metadata_load_finish() and pass the right flags
depending on whether comment and profile were loaded. Also, set the
profile before creating the layer so its space is correct
automatically.

...in both the core and libgimp.

Images now know what the default mode for new layers is:

- NORMAL for empty images
- NORMAL for images with any non-legacy layer
- NORMAL_LEGAVY for images with only legacy layers

This changes behavior when layers are created from the UI, but *also*
when created by plug-ins (yes there is a compat issue here):

- Most (all?) single-layer file importers now create NORMAL layers
- Screenshot, Webpage etc also create NORMAL layers

Scripts that create images from scratch (logos etc) should not be
affected because they usually have NORMAL_LEGACY hardcoded.

3rd party plug-ins and scripts will also behave old-style unless they
get ported to gimp_image_get_default_new_layer_mode().

instead of hardcoding NORMAL_LEGACY.

and make NORMAL_LEGACY immutable.

with proper value names. Mark most values as _BROKEN because they use
weird alpha compositing that has to die. Move GimpLayerModeEffects to
libgimpbase, deprecate it, and set it as compat enum for GimpLayerMode.
Add the GimpLayerModeEffects values as compat constants to script-fu
and pygimp.

... when it's appropriate.

and shorten a function name.

Don't skip the first 10 bytes. That code was there to skip the magic
"GIMP_XMP_1" of the old "gimp-metadata" parasite. Instead, properly
check for that magic in xcf_load_image() and pass only the actual XMP
to gimp_metadata_set_from_xmp(). Also remove the +10 hack in file-exr.

This commit needs review as it uses an ugly hack to make
gimp_metadata_set_from_xmp() do what it wants.

This generates an ICC profile from the embedded white point and
chromaticities on the fly, assuming linear gamma images.

so the user gets feedback as early as possible.

- Add new enum GimpComponentType which contains u8, u16, u32 etc.
- Change GimpPrecision to be u8-linear, u8-gamma, u16-linear etc.
- Add all the needed formats to gimp-babl.c
- Bump the XCF version to 5 and make sure version 4 with the old
  GimpPrecision enum values is loaded correctly

This change blows up the precision enums in "New Image" and
Image->Precision so we can test all this stuff. It is undecided what
format will be user-visible options in 2.10.

This is a basic implementation of an OpenEXR loader. This
"infrastructure" is required for any further work. It consists of:

* The build system changes.

* A C wrapper around the OpenEXR library, which is necessary as it's not
  possible to intermix GIMP's code with C++ code.

* A basic image loader. Chroma is not supported currently, and some
  other weird files like multi-view files are unsupported. These can be
  added when necessary. There is no UI, but it should be straightforward
  to add new features like this on top of this work.