...always AdobeRGB!
Change all file plug-ins to never call gimp_image_metadata_load_finish()
with the GIMP_METADATA_LOAD_COLORSPACE when they loaded a color profile.
This keeps gimp_image_metadata_load_finish() from assigning a profile
from DCT even if the loaded profile was GIMP's built-in sRGB.
Instead of treating any unspecified TIFF channel as non-premultiplied
alpha, let's now ask the user (in non-interactive case, we continue
defaulting to non-premultiplied channel and outputing a message). The 3
choices are: premultiplied, non-premultiplied (which is the default so
you can just hit Enter and get same result as previously) and channel.
It's still not perfect as it still assumes that an alpha channel will
necessarily be the first extra channel (though the spec does not mandate
such assumption). Let's say for now that it is enough. Using extra
channels for the alpha channel only is most likely the most common usage
(actually the spec only has specific types for such usage).
Jehan