title: fbtorch: cmake can not find torch directories
body: <p>I am trying to build and install fbtorch, however when I used cmake I got the following error:</p>
  
  <pre><code>CMake Error at CMakeLists.txt:9 (FIND_PACKAGE):
    By not providing "FindTorch.cmake" in CMAKE_MODULE_PATH this project has
    asked CMake to find a package configuration file provided by "Torch", but
    CMake did not find one.
  
    Could not find a package configuration file provided by "Torch" with any of
    the following names:
  
      TorchConfig.cmake
      torch-config.cmake
  
    Add the installation prefix of "Torch" to CMAKE_PREFIX_PATH or set
    "Torch_DIR" to a directory containing one of the above files.  If "Torch"
    provides a separate development package or SDK, be sure it has been
    installed.
  </code></pre>
  
  <p>I searched online and found some solutions such as using</p>
  
  <pre><code>source ~/torch/install/bin/torch-activate
  </code></pre>
  
  <p>or reinstalling torch, but nothing helps.
  Could someone help me? Thank you.</p>