OpenEXR has many compression codecs exposed, with some of them arguably
not very useful. Generally, for lossless compression you want ZIP or PIZ,
and for lossy compression you want DWAA/DWAB. Reorder the dropdown
entries so that these are at the top just below "No compression".
Previously the not-really-great choice of Pxr24 was the first.
Add tooltips to all the compression codecs too, trying to explain
what each of them does in once sentence.