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/animation/animation_player.cpp

@@ -30,8 +30,8 @@
 
 #include "animation_player.h"
 
-#include "core/engine.h"
-#include "core/message_queue.h"
+#include "core/config/engine.h"
+#include "core/object/message_queue.h"
 #include "scene/scene_string_names.h"
 #include "servers/audio/audio_stream.h"