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/file_access_encrypted.cpp

@@ -32,8 +32,8 @@
 
 #include "core/crypto/crypto_core.h"
 #include "core/os/copymem.h"
-#include "core/print_string.h"
-#include "core/variant.h"
+#include "core/string/print_string.h"
+#include "core/variant/variant.h"
 
 #include <stdio.h>