[File formats] Add OpenRaster support #686
Description
Requested feature
We could just open the mergedimage.png on import, which is the final result of the file.
Possible drawbacks
Probably none for importing. Saving would a little bit more thought.
Possible alternatives
Alternative would be to try to recreate the image from the 'stack.xml', but that's probably too much effort for no gain, as Drawing doesn't use layers.
Use case
Some programs (like Pinta, MyPaint, GIMP and Krita), allow saving files in the OpenRaster format. Would be useful to be able to open those.