ab85c5f980
With multiview/multilayer OpenEXR file, `load_image_single()` will return NULL ibuf, since it has already populated ima (with `image_create_multiview()` or `image_create_multilayer()` calls). Also, added some more checks before doing `IMB_ImBufFromStereo3d()`, to be sure we do have enough slots in ibuf_arr, and we do not overwrite second ibuf either.