Support for pytorch1.4.0

[kwea123]

Currently, the code cannot compile with torch 1.4.0 (it can work with 1.3.1). It produces lots of "... is deprecated" warnings and finally an error which prevents it from compiling:

src/inplace_abn.cpp: In function ‘void pybind11_init__backend(pybind11::module&)’:
src/inplace_abn.cpp:145:107: error: no matching function for call to ‘pybind11::module::def(const char [9], <unresolved overloaded function type>, const char [74])’
   m.def("backward", &backward, "Second step of the backward pass. This is an in-place operation w.r.t. dy");
                                                                                                           ^
In file included from /home/ubuntu/anaconda3/envs/test/lib/python3.6/site-packages/torch/include/torch/csrc/utils/pybind.h:6:0,
                 from /home/ubuntu/anaconda3/envs/test/lib/python3.6/site-packages/torch/include/torch/csrc/api/include/torch/python.h:12,
                 from /home/ubuntu/anaconda3/envs/test/lib/python3.6/site-packages/torch/include/torch/extension.h:6,
                 from src/inplace_abn.cpp:3:
/home/ubuntu/anaconda3/envs/test/lib/python3.6/site-packages/torch/include/pybind11/pybind11.h:810:13: note: candidate: template<class Func, class ... Extra> pybind11::module& pybind11::module::def(const char*, Func&&, const Extra& ...)
     module &def(const char *name_, Func &&f, const Extra& ... extra) {
             ^
/home/ubuntu/anaconda3/envs/test/lib/python3.6/site-packages/torch/include/pybind11/pybind11.h:810:13: note:   template argument deduction/substitution failed:
src/inplace_abn.cpp:145:107: note:   couldn't deduce template parameter ‘Func’
   m.def("backward", &backward, "Second step of the backward pass. This is an in-place operation w.r.t. dy");
                                                                                                           ^
error: command 'gcc' failed with exit status 1

[ducksoup]

@kwea123 These are fixed in the latest release.