python: Add adapter modules when VTK_ENABLE_KITS is ON

Some Python scripts explicitly import from named submodules as opposed to from
the top-level vtk module. When VTK_ENABLE_KITS is ON those modules might not
exist. This results in ImportErrors, like the one shown below when running the
vtkFiltersCorePython-pointsPrecisions test:

    Traceback (most recent call last):
      File "C:/dev/VTK/Filters/Core/Testing/Python/pointsPrecisions.py", line 3, in <module>
	from vtk.vtkCommonCore import vtkPoints, vtkDoubleArray, vtkIdList
    ImportError: No module named vtkCommonCore

This commit adds adapter modules to allow such scripts to run unmodified when
VTK_ENABLE_KITS is ON.

Author: msmolens

Wrapping/Python/CMakeLists.txt

@@ -299,6 +299,18 @@ if(PYTHON_EXECUTABLE)
   list(APPEND VTK_PYTHON_FILES
     "${CMAKE_CURRENT_BINARY_DIR}/vtk/__init__.py")
 
+# Kit module adapters
+  foreach(kit IN LISTS vtk_kits)
+    set(_module_kit ${kit}${VTK_KIT_SUFFIX})
+    foreach(dep IN LISTS _${kit}_modules)
+      file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/vtk/${dep}")
+      configure_file(vtk/kit_module__init__.py.in vtk/${dep}/__init__.py @ONLY)
+      list(APPEND VTK_PYTHON_FILES
+        "${CMAKE_CURRENT_BINARY_DIR}/vtk/${dep}/__init__.py")
+    endforeach()
+  endforeach()
+  unset(_module_kit)
+
 # vtk.util package
   list(APPEND VTK_PYTHON_FILES
     vtk/util/__init__

Wrapping/Python/vtk/kit_module__init__.py.in

@@ -0,0 +1,9 @@
+"""
+This module is an adapter for scripts that explicitly import from named
+submodules as opposed to from the top-level vtk module. This is necessary
+because the specific submodules might not exist when VTK_ENABLE_KITS is enabled.
+"""
+
+from __future__ import absolute_import
+
+from ..@_module_kit@ import *