This aligns with the VFX reference platform 2020 along with the decision
to stick to Python 3.7, see T68774.
Blosc was downgraded to 1.5 as recommended by the OpenVDB documentation.
IlmBase and OpenEXR are now built together with CMake rather separately
using autoconf.
Differential Revision: https://developer.blender.org/D6593
-expanded build_deps.cmd with 2017 support, it can't locate msvc2017 so needs to be run from developer prompt.
-Newer cmake was unhappy with openal's cmakelists.txt
-collada has warning as error on and errored out on new msvc2017 warnings.
Note these are intended for platform maintainers, we do not intend to
support users making their own builds with these. For that precompiled
libraries from lib/ should be used.
Implemented by Martijn Berger, Ray Molenkamp and Brecht Van Lommel.
Differential Revision: https://developer.blender.org/D2753
