OpenEXR 2.2 support, esp. for the new DWAA/DWAB compression modes.
Median filter: IBA::median_filter and oiiotool --median.

Median filters can be good for removing high-frequency outlier value
noise, but without also blurring edges like a blurring filter would do.

Also, IBA::unsharp_mask and oiiotool --unsharp, if you say "median" for
the kernel, will use a median filter rather than the gaussian blur for
the smoothing step of the unsharp mask. This tends to have the effect of
sharpening small details, while not over-sharpening long edges as the
traditional unsharp mask sometimes does.
string_view-ize ImageBufAlgo
Fully string_view-ize ImageBuf
iinfo/oiiotool -v: don't spew endlessly for subframe resolutions on movies
Tell gcc/clang to ignore the fact that math functions can set errno (helps codegen of sqrtf in particular)
Build scripts minor reformatting and better help messages.
* Rearrange Makefile wrapper so that 'make help' is much more readable.
* Some minor reformatting and movement to make it align to similar constructs
  in the OSL Makefile and CMakeLists.txt (makes it easier to diff and port
  improvements in the build system from one project to another).
testtex enhancements: --nchannels, --derivs

--nchannels lets you force the number of channels to look up (it used to
automatically use the number of channels in the map, and this is still
the default). The purpose is to be able to test when the number of channels
in the lookup differs from the number in the map.

--derivs makes the variety of texture call that looks up derivatives of the
texture as well, and outputs them as two additional images (one for ds,
one for dt). This lets us test that the derivatives are calculated correctly.
Merge branch 'master' of https://github.com/OpenImageIO/oiio into metadata