* Also pass torch includes to nvcc build
* Export ATen/cuda headers with install
* Refactor flags common to C++ and CUDA
* Improve tests for C++/CUDA extensions
* Export .cuh files under THC
* Refactor and clean cpp_extension.py slightly
* Include ATen in cuda extension test
* Clarifying comment in cuda_extension.cu
* Replace cuda_extension.cu with cuda_extension_kernel.cu in setup.py
* Copy compile args in C++ extension and add second kernel
* Conditionally add -std=c++11 to cuda_flags
* Also export cuDNN headers
* Add comment about deepcopy
