text: Title: CMake Error at C:/dlib-19.6/dlib/cmake_utils/add_python_module:116 (message):    Boost python library not found. Call Stack (most recent call first):   CMakeLists.txt:9 (include) -- Configuring incomplete, errors occurred! See also "C:/dlib-19.6/tools/python/build/CMakeFiles/CMakeOutput.log". error: cmake configuration failed!
  Body: * face_recognition version: 
  * Python version: 3.5
  * Operating System: windows 10
  
  ### Description
  
  trying to install face_recognition library
  
  ### What I Did
  
  ```
  C:\dlib-19.6>python setup.py install
  running install
  running bdist_egg
  running build
  Detected Python architecture: 64bit
  Detected platform: win32
  Removing build directory C:\dlib-19.6\./tools/python/build
  Configuring cmake ...
  -- Building for: Visual Studio 15 2017
  -- The C compiler identification is MSVC 19.15.26730.0
  -- The CXX compiler identification is MSVC 19.15.26730.0
  -- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.15.26726/bin/Hostx86/x86/cl.exe
  -- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.15.26726/bin/Hostx86/x86/cl.exe -- works
  -- Detecting C compiler ABI info
  -- Detecting C compiler ABI info - done
  -- Detecting C compile features
  -- Detecting C compile features - done
  -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.15.26726/bin/Hostx86/x86/cl.exe
  -- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/Community/VC/Tools/MSVC/14.15.26726/bin/Hostx86/x86/cl.exe -- works
  -- Detecting CXX compiler ABI info
  -- Detecting CXX compiler ABI info - done
  -- Detecting CXX compile features
  -- Detecting CXX compile features - done
  CMake Warning at C:/Program Files/CMake/share/cmake-3.12/Modules/FindBoost.cmake:1727 (message):
    No header defined for python-py34; skipping header check
  Call Stack (most recent call first):
    C:/dlib-19.6/dlib/cmake_utils/add_python_module:61 (FIND_PACKAGE)
    CMakeLists.txt:9 (include)
  -- Could NOT find Boost
  CMake Warning at C:/Program Files/CMake/share/cmake-3.12/Modules/FindBoost.cmake:1727 (message):
    No header defined for python-py35; skipping header check
  Call Stack (most recent call first):
    C:/dlib-19.6/dlib/cmake_utils/add_python_module:63 (FIND_PACKAGE)
    CMakeLists.txt:9 (include)
  -- Could NOT find Boost
  -- Could NOT find Boost
  -- Could NOT find Boost
  -- Found PythonLibs: C:/Users/DELL/Anaconda3/libs/python36.lib (found suitable version "3.6.5", minimum required is "3.4")
  --  *****************************************************************************************************
  -- We couldn't find the right version of boost python.  If you installed boost and you are still getting this error then you might have installed a version of boost that was compiled with a different version of visual studio than the one you are using.  So you have to make sure that the version of visual studio is the same version that was used to compile the copy of boost you are using.
  --  Set the BOOST_ROOT and BOOST_LIBRARYDIR environment variables before running cmake.
  --  E.g.  Something like this:
  --     set BOOST_ROOT=C:\local\boost_1_57_0
  --     set BOOST_LIBRARYDIR=C:\local\boost_1_57_0\stage\lib
  --
  --  You will also likely need to compile boost yourself rather than using one of the precompiled
  --  windows binaries.  Do this by going to the folder tools\build\ within boost and running
  --  bootstrap.bat.  Then run the command:
  --     b2 install
  --  And then add the output bin folder to your PATH.  Usually this is the C:\boost-build-engine\bin
  --  folder. Finally, go to the boost root and run a command like this:
  --     b2 -a --with-python address-model=64 toolset=msvc runtime-link=static
  --  When it completes, set BOOST_LIBRARYDIR equal to wherever b2 put the compiled libraries.
  --  Note that you will need to set the address-model based on if you want a 32 or 64bit python library.
  --
  --  Next, when you invoke cmake to compile dlib you may have to use cmake's -G option to set the
  --  64 vs. 32bit mode of visual studio.  Also, if you want a Python3 library you will need to
  --  add -DPYTHON3=1.  You do this with a statement like:
  --     cmake -G "Visual Studio 12 2013 Win64" -DPYTHON3=1 ..\..\tools\python
  --  Rather than:
  --     cmake ..\..\tools\python
  --  Which will build a 32bit Python2 module by default on most systems.
  --
  --  *****************************************************************************************************
  CMake Error at C:/dlib-19.6/dlib/cmake_utils/add_python_module:116 (message):
     Boost python library not found.
  Call Stack (most recent call first):
    CMakeLists.txt:9 (include)
  -- Configuring incomplete, errors occurred!
  See also "C:/dlib-19.6/tools/python/build/CMakeFiles/CMakeOutput.log".
  error: cmake configuration failed!
  ```
  