Windows: allow "Edit and continue" in debug configuration

cmake/BornAgain/Windows.cmake

@@ -13,3 +13,6 @@ message(STATUS "Disabling static align for Eigen")
 
 string(APPEND CMAKE_CXX_FLAGS " /MD /MP /D_USE_MATH_DEFINES /wd4005 /wd4244 -I${CMAKE_SOURCE_DIR}/Wrap -FIw32pragma.h")
 # string(APPEND CMAKE_SHARED_LINKER_FLAGS " /NODEFAULTLIB:libcmtd.lib")
+
+# --- switch ON edit and continue; only in DEBUG configuration
+add_compile_options($<$<CONFIG:Debug>:/ZI>)