TIFF: gracefully handle negative origin without asserting in libtiff
Move platform macros from sysutil.h to platform.h
Add OIIO_FORCEINLINE definition
ustring: add comparisons between ustrings versus char* and string_view.
This fixes some potential ambiguities in method selection.
OpenEXR 2.2 support, esp. for the new DWAA/DWAB compression modes.