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

modules/gdnative/pluginscript/pluginscript_loader.h

@@ -34,7 +34,7 @@
 // Godot imports
 #include "core/io/resource_loader.h"
 #include "core/io/resource_saver.h"
-#include "core/script_language.h"
+#include "core/object/script_language.h"
 
 class PluginScriptLanguage;