Add 'xo-refcnt/' from commit 'bcd86e5324'

git-subtree-dir: xo-refcnt
git-subtree-mainline: ce2fc80bfd
git-subtree-split: bcd86e5324

xo-refcnt/src/Displayable.cpp

@@ -0,0 +1,16 @@
+/* @file Displayable.cpp */
+
+#include "Displayable.hpp"
+
+namespace xo {
+    using xo::tostr;
+
+    namespace ref {
+        std::string
+        Displayable::display_string() const {
+            return tostr(*this);
+        } /*display_string*/
+    } /*namespace ref*/
+} /*namespace xo*/
+
+/* end Displayable.cpp */