BUG: Fix COMPILE_DEFINITIONS of castxml
BUG: Fix COMPILE_DEFINITIONS of castxml

itk_wrap_module_castxml now gets the COMPILE_DEFINITIONS of the
module top directory, instead of the wrapping directory.

The old behavior wasn't respecting the add_compile_definitions
set in the CMakeLists of the module.

Triggered by:
https://github.com/InsightSoftwareConsortium/ITKTotalVariation/pull/5

This is a follow on from: e3a908b49b569be0690227614f8e230262ac7bc2

richardbeare/ITK,hjmjohnson/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,hjmjohnson/ITK,hjmjohnson/ITK,LucasGandel/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,thewtex/ITK,vfonov/ITK,richardbeare/ITK,BRAINSia/ITK,LucasGandel/ITK,hjmjohnson/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,Kitware/ITK,malaterre/ITK,Kitware/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,Kitware/ITK,thewtex/ITK,malaterre/ITK,LucasGandel/ITK,richardbeare/ITK,hjmjohnson/ITK,BRAINSia/ITK,LucasGandel/ITK,BRAINSia/ITK,vfonov/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,vfonov/ITK,vfonov/ITK,Kitware/ITK,hjmjohnson/ITK,Kitware/ITK,vfonov/ITK,LucasGandel/ITK,vfonov/ITK,vfonov/ITK,thewtex/ITK,Kitware/ITK,malaterre/ITK,thewtex/ITK,malaterre/ITK,thewtex/ITK,malaterre/ITK,vfonov/ITK,thewtex/ITK,malaterre/ITK,BRAINSia/ITK,BRAINSia/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,LucasGandel/ITK,malaterre/ITK,Kitware/ITK,hjmjohnson/ITK,BRAINSia/ITK,richardbeare/ITK,vfonov/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK