windows: Add Visual Studio runtime libraries to itk-core

This addresses the error:

	import _ITKPyBasePython
	ImportError: DLL load failed:

On Windows when: Visual Studio is not installed on the system, or the
vc_redist.x64.exe Visual Studio C++ redistributables are not installed,
or Anaconda is not used (Anaconda ships the redistributable dll's in a
vc2015_runtime package when Python is installed).

With DependencyWalker, we can observe that the _ITKPyBasePython.pyd dll
requires vcruntime140.dll, vcruntime140_1.dll, and msvcp140.dll. CPython
from python.org ships with vcruntime140.dll for Python 3.5, 3.6, 3.7, and
3.8. Experimentally, if we add msvcp140.dll to the itk/ package
directory, the import succeeds. This patch adds all three libraries plus
an additional library with the CMake InstallRequiredSystemLibraries
module to the itk-core package.

For more information, see this blog post by Steve Dower:

  https://stevedower.id.au/blog/building-for-python-3-5-part-two

Thanks to Jean-Christophe Fillion-Robin for the helpful discussion.

Author: thewtex

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.3)
 
-project(ITKPythonPackage NONE)
+project(ITKPythonPackage CXX)
 
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
 include(ITKPythonPackage)
@@ -488,6 +488,14 @@ else()
 
   endif()
 
+  if(MSVC AND ITKPythonPackage_WHEEL_NAME STREQUAL "itk-core")
+    message(STATUS "Adding install rules for compiler runtime libraries")
+    # Put the runtime libraries next to the "itk/_*.pyd" C-extensions so they
+    # are found.
+    set(CMAKE_INSTALL_SYSTEM_RUNTIME_DESTINATION "itk")
+    include(InstallRequiredSystemLibraries)
+  endif()
+
   #-----------------------------------------------------------------------------
   # Install ITK components
   message(STATUS "Adding install rules for components:")