Release 2.3.8 (1 Oct 2021) -- compared to 2.3.7

• Fix ImageBuf::read() bug for images of mixed per-channel data types. #3088
• Fix crash that could happen with invalidly numbered UDIM files. #3116
• Better catching of exceptions and other error handling when OpenColorIO 1.x is used but encounters an OpenColorIO 2.x config file. #3089 #3092 #3095
• Ensure that OpenColorIO doesn't send info messages to the console if no config is found. #3113
• Fix: make sure ImageSpec deserialization works for arbitrary attribs. #3066
• oiiotool -ch now has greatly reduced cost (no useless allocations or copies) when the channel order and names don't change. #3068
• oiiotool --runstats is now much better about correctly attributing I/O time to -i instead of to the subsequent operations that triggers the read. #3073
• TIFF output now supports IO proxies. #3075 #3077
• Improved finding of fonts (by IBA::render_text and oiiotool --text). It now honors environment variable $OPENIMAGEIO_FONTS and global OIIO attribute "font_searchpath" to list directories to be searched when fonts are needed. #3096
• We no longer install a FindOpenImageIO.cmake module. It was incomplete, out of date, and wholly unnecessary now that we correctly export a config file OpenImageIOConfig.cmake and friends. #3098
• When building against OpenEXR 3.1+, use of the OpenEXRCore library no longer requires a build-time option, but instead is always available (though off by default) and can be enabled by an application setting the OIIO global attribute "openexr:core" to 1. #3100
• dev: Timer::add_seconds and add_ticks methods. #3070
• dev: Add round_down_to_multiple() and improve round_to_multiple() to correctly handle cases where the value is less than 0. #3104