Problem: code duplication in get_address of ipc/tcp/tipc listener classes

Solution: pull up to base class

src/tipc_address.hpp

@@ -55,7 +55,7 @@ class tipc_address_t
     int resolve (const char *name);
 
     //  The opposite to resolve()
-    int to_string (std::string &addr_);
+    int to_string (std::string &addr_) const;
 
     // Handling different TIPC address types
     bool is_service () const;