Cuda(10.1) torchvision missing arch fix

The method of setting environment variables struggles with ";" separated lists, as CMake sees both space and ; as list separators. This became a problem when attempting to build torch for multiple NVIDIA platforms, where only the first ended up being built. This merge introduces the keyword "semicolon" for ENVIRONENT, which is is replaced with a ";" when running cmake.

Additionally torch and torchvision are updated. Torch 1.14 is the last release which supports python2. https://github.com/pytorch/pytorch/releases/tag/v1.4.0