Move address << operator implementation out of header

lokimq/address.cpp

@@ -4,6 +4,7 @@
 #include "base64.h"
 #include <tuple>
 #include <limits>
+#include <iostream>
 
 namespace lokimq {
 
@@ -328,4 +329,6 @@ address address::ipc_curve(std::string path, std::string pubkey) {
     return a;
 }
 
+std::ostream& operator<<(std::ostream& o, const address& a) { return o << a.full_address(); }
+
 }

lokimq/address.h

@@ -183,6 +183,6 @@ struct address {
 };
 
 // Outputs address.full_address() when sent to an ostream.
-std::ostream& operator<<(std::ostream& o, const address& a) { return o << a.full_address(); }
+std::ostream& operator<<(std::ostream& o, const address& a);
 
 }