Release 2.2.18 (1 Sep 2021) -- compared to 2.2.17 Honor env variable CUE_THREADS (used by OpenCue) to set the default size of OIIO's thread pool. #3038 Compatibility with OpenColorIO 2.1. #3050 Dev: Extend Sysutil::getenv() to take a default if the environment variable is not found. #3047 #3048