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

editor/editor_plugin_settings.cpp

@@ -30,10 +30,10 @@
 
 #include "editor_plugin_settings.h"
 
+#include "core/config/project_settings.h"
 #include "core/io/config_file.h"
 #include "core/os/file_access.h"
 #include "core/os/main_loop.h"
-#include "core/project_settings.h"
 #include "editor_node.h"
 #include "editor_scale.h"
 #include "scene/gui/margin_container.h"