[WINDOWS] contrib hook to create dll on windows

Currently, we rely on https://github.com/dmlc/tvm/blob/master/python/tvm/contrib/cc.py#L7 to call gcc in the environment to create a shared library that can be loaded later.

This won't work under windows when MSVC is used as the main compiler. It would be great to add a patch to invoke MSVC command line(link.exe or cl.exe) to create the dll library as we did under linux. 