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/localization_editor.cpp

@@ -30,7 +30,7 @@
 
 #include "localization_editor.h"
 
-#include "core/translation.h"
+#include "core/string/translation.h"
 #include "editor_node.h"
 #include "editor_translation_parser.h"
 #include "pot_generator.h"