add PISet::const_iterator, now can iterate ranged-for PISet by T, not by PIPair<T, bool>

utils/value_tree_translator/main.cpp

@@ -285,10 +285,10 @@ int main(int argc, char * argv[]) {
 	ts << "<context>\n";
 	ts << "  <name>" << context << "</name>\n";
 	for (const auto & s: strings) {
-		TSMessage m = old.value(s.first);
-		m.filename  = locations.value(s.first.hash());
-		writeTSMessage(s.first, m);
-		old.remove(s.first);
+		TSMessage m = old.value(s);
+		m.filename  = locations.value(s.hash());
+		writeTSMessage(s, m);
+		old.remove(s);
 	}
 	if (!cli.hasArgument("no-obsolete")) {
 		for (const auto & i: old) {