Log Message:
openimageio: update to 2.2.15.1

Release 2.2.15.1 (3 Jun 2021) -- compared to 2.2.15.0
-----------------------------------------------------
* Fix crash / misbehavior in ustring internals on Apple M1 ARM.

Release 2.2.15 (1 Jun 2021) -- compared to 2.2.14
--------------------------------------------------
* BMP improvements: now support reading rle-compressed BMP files; writing
  single channel grayscale images now save as 8bpp palette images intead of
  24bpp; and reading 8bpp where all palette entries have R==G==B looks like
  a 1-channel grayscale instead of 3-channel RGB.
* Bug: IBA::render_text did not properly account for alpha of the draw
  color.
* Bug: Fix runaway parsing time for pathological XMP metadata.
* Bug: Fixed a crash is ImageCacheFile::read_unmipped when sampling
* Fix exported cmake config files, which could fail if Imath and OpenEXR
  weren't the at the same version number.
* Build: Modernize cmake to use targets for PNG and ZLIB.
* Build: Fix to accommodate upcoming OpenColorIO 2.1 deprecation of
  parseColorSpaceFromString.
* Build: Changes to make it build against TBB 2021.
* Dev: Add Strutil functions: find, rfind, ifind, irfind.
  non-zero-base channels.

Release 2.2.14 (1 May 2021) -- compared to 2.2.13
--------------------------------------------------
* JPEG: Improve readin of files with mildly corrupted headers.
* TIFF: Support IOProxy for input.
* BMP: Improve performance by eliminating wasteful per-scanline allocation
  and needless data copying.
* Build/CI: Fix all the build_*.bash scripts to not use cmake --config flag,
  which was harmlessly ignored but is flagged as an error for CMake 3.20.
* Build: More fixes related to supporting a wide range of OpenEXR versions,
  and making our exported cmake configs correctly transmit dependencies on
  OpenEXR include paths.
* ImageBufAlgo::fillholes_pushpull: added logic to correctly set the spec's
  alpha_channel field when generating sub-images.
* Python: MakeTxBumpWithSlopes enum value had been inadvertently omitted
  from the Python bindings.

Release 2.2.13 (1 Apr 2021) -- compared to 2.2.12
--------------------------------------------------
* Get ready for upcoming Imath/OpenEXR 3.0 release.
* GIF: Fix error checking for non-existant GIF files.
* Fix crash related to ImageBuf:set_write_format() when used in conjunction
  with a file format that doesn't support per-channel data types.
* Make RAW files handle Unicode filenames on Windows.
* Make sure OIIO builds cleanly with C++20.
* BMP: Several bug fixes when reading an older (V1) variety of BMP files.
* Targa: fix reading tga files with 0-sized thumbnails.
* TIFF: fix reading of certain tiled TIFF files with the vertical image size
  is not a whole multiple of the tile size.
* Avoid OpenColorIO v2 exception when color-conversion of single points (we
  didn't pass a correct stride, thinking that stride isn't used for a single
  point).
* make_texture: When outputting to a 'half' data format file, clamp filtered
  values to the half range so large values don't inadvertently get converted
  to half 'infinite' values.
* Improvements to ustring internals to ensure that no two ustrings ever end
  up with the same hash() value.
* Fixes for compiler errors when compiling farmhash.h using C++11 mode with
  newer gcc (6+).

Release 2.2.12 (1 Mar 2021) -- compared to 2.2.11
--------------------------------------------------
* Bug fix: Improve parsing of XMP records in metadata: more correct handling
  of lists/sequences, better inference of types that look like int or float
  (rather than forcing unknown fields into strings), fixed bugs in parsing
  rational values.
* Bug fix: Fix loading PSB files with cinf tags.
* Build: Improvements to building or linking static libraries.
* Build: Change default STOP_ON_WARNING to OFF for release branches
  (including this one) so that small change in compiler warnings after our
  release don't break anybody's builds. (Though we still stop on warnings
  for CI builds).
* Build: More clear warnings about using OpenVDB 8+ when building for C++11,
  because OpenVDB 8 requires C++14 or higher.
* Build: The pkgconfig OpenImageIO.pc was specifying the include path
  incorrectly.
* Build: More gracefully handle building against a custom Imath/OpenEXR even
  when another exists in the system area.
* Build: Minor fixes to build cleanly against the upcoming Imath 3.0.
* Dev: hash.h: Make many of the hash functions constexpr.
* Dev: Better unit tests to verify correctness and stability over time of
  the hash functions.
* Dev: unordered_map_concurrent.h: New methods find_or_insert, nobin_mask().
* CI: Speed up CI builds by not building OpenEXR example programes.
* CI: Speed up CI by using GitHub 'cache' actions + ccache.
* CI: Separate stages (setup, deps, build, test) into separate GHA "steps"
  for better logging and understanding of the timing and performance.
* CI: Now actively testing libheif in Linux CI.
* CI: Remove the last vestiges of Travis-CI, which we no longer use.
* CI: For failed tests, add CMake cache and log part of the saved artifacts.
* PSA: Avoid libheif 1.10 on Mac, it is broken. Libheif 1.11 is fine.

Release 2.2.11.1 (1 Feb 2021) -- compared to 2.2.11.0
-----------------------------------------------------
* Fix build break against Qt 5.15.2 (deprecated enum).

Release 2.2.11 (1 Feb 2021) -- compared to 2.2.10
--------------------------------------------------
* Enabled AVIF decoding of heic files (requires libheif >= 1.7 and for it
  to have been built with an AV1 encoder/decoder).
* `oiiotool --help` now prints the OCIO version (where it prints the config
  file and known color space).
* Bug fix: ImageBufAlgo::ociolook() and ociofiletransform() internally
  reversed the order of their `inverse` and `unpremult` arguments, making it
  hard to select the inverse transformation.
* Fix memory leak during decoding of some invalid Exif blocks.
* Build: No longer directly link against python libraries when unnecessary.
* Build: Better finding of OpenJpeg 2.4.
* Build: On Windows, fix some linkage problems by changing the pybind11
  bindings to make a CMake "shared" library rather than \ 
"module". Sounds
  wrong, but seems to work. We will reverse if this causes problems.
* Build: On Mac, libheif 1.10 is very broken. Don't use that version.
* Build: Fix build break against changes coming in future libtiff, where it
  is changing from some libtiff-defined integer types to the equivalent
  stdint.h types.
* Build: Some final touches to prepare for release of OpenColor 2.0.
* Build: Fixes to support the libraw 202101 snapshot (their in-progress
  0.21.0).
* CI: Got Windows CI fully working, bit by bit.
* Dev: Some internal rearrangement of span.h and string_view.h (that should
  not break source or ABI compatibility). `std::size()` and `std::ssize()`
  should work with OIIO::span and OIIO::string_view now.
* Dev: ustring internals now have a way to ask for the list of ustrings
  whose hashses collided.
* Dev: New Filesystem::generic_filepath() returnss a filepath in generic
  format (not OS specific).
* Dev: ArgParse::abort() lets the response to a command line argument signal
  that no further arguments should be parsed.
* Dev: In oiioversion.h, added macros `OIIO_VERSION_GREATER_EQUAL` and
  `OIIO_VERSION_LESS`.
* Dev: In platform.h, added macro OIIO_INLINE_CONSTEXPR, which is equivalent
  to `inline constexpr` for C++17, but just constexpr for C++ <= 14.