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

core/io/translation_loader_po.cpp

@@ -31,8 +31,8 @@
 #include "translation_loader_po.h"
 
 #include "core/os/file_access.h"
-#include "core/translation.h"
-#include "core/translation_po.h"
+#include "core/string/translation.h"
+#include "core/string/translation_po.h"
 
 RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error) {
 	enum Status {