Support big-endian PFM images

[Peregrine05]

Currently, attempting to load a big-endian PFM image results in the following error:

Error: big-endian PFM images are not supported

[atafra]

We're not planning to support this by default but it should work if you build with OpenImageIO support. Also, please note that the included applications are only for development/testing, not end-user applications.

[Calinou]

We're not planning to support this by default but it should work if you build with OpenImageIO support

Could OpenImageIO be enabled in future official binary releases? This would smoothen out the workflow a lot when using OpenImageDenoise on OpenEXR images.

Right now, I have to do the following which requires ImageMagick:

convert test.exr -endian LSB /tmp/test.pfm \
  && oidnDenoise --filter RTLightmap --hdr /tmp/test.pfm --output /tmp/test_denoised.pfm \
  && convert /tmp/test_denoised.pfm test.exr

[atafra]

No, sorry. The included applications were not intended to be used in production, these are just samples.