Fixed missing build type subfolders in batch files.

Newer CMake versions seem to recursively replace all @ variables
in one configure_file(.... @ONLY) call. This lead to replacing
@VS_BUILD_TYPE@ in the MITK_RUNTIME_PATH variable with nothing when
configuring the MITKConfig.cmake.in file. Applications (like ExtApp)
do a find_package(MITK) and get the MITK_RUNTIME_PATH variable from
the MITKConfig.cmake file, which was then missing the @VS_BUILD_TYPE@
strings for later substitution. This is worked around now by using
the %VS_BUILD_TYPE% placeholder in the MITK_RUNTIME_PATH variable
and substituting it manually in the mitkFunctionCreateWindowsBatchScript
macro.