* Rename autograd namespace to torch and change torch.h into python.h
* Pave the way for torch::nn::Module
* Reorganize module code structure
* Undo ONNX update
* Remove sleef submodule
* Rename autograd namespace to torch and change torch.h into python.h
* Include torch.h instead of python.h in test/cpp/api
* Change some mentions of torch.h to python.h in C++ extensions
* Set paths directly, without find_path
