Reorganized core/ directory, it was too fatty already

-Removed FuncRef, since Callable makes it obsolete
-Removed int_types.h as its obsolete in c++11+
-Changed color names code

scene/main/node.cpp

@@ -32,8 +32,8 @@
 
 #include "core/core_string_names.h"
 #include "core/io/resource_loader.h"
-#include "core/message_queue.h"
-#include "core/print_string.h"
+#include "core/object/message_queue.h"
+#include "core/string/print_string.h"
 #include "instance_placeholder.h"
 #include "scene/debugger/scene_debugger.h"
 #include "scene/resources/packed_scene.h"