CMake: Set Visual Studio working directory

Use the executable output directory for samples and demos, use the source directory for tests.

build/cmake/demos/CMakeLists.txt

@@ -38,6 +38,9 @@ function(wx_add_demo name)
     target_link_libraries(${DEMO_NAME} core ${DEMO_LIBRARIES})
     wx_set_common_target_properties(${DEMO_NAME})
     set_target_properties(${DEMO_NAME} PROPERTIES FOLDER "Demos")
+    set_target_properties(${DEMO_NAME} PROPERTIES
+        VS_DEBUGGER_WORKING_DIRECTORY "${wxOUTPUT_DIR}/${wxCOMPILER_PREFIX}${wxARCH_SUFFIX}_${lib_suffix}"
+        )
 endfunction()
 
 wx_add_demo(bombs