namespace: try to resolve ndn and std conflicts

Change-Id: I141ead4b8f30ce75bae73974e47e6e5acd75a296
diff --git a/src/start-chat-dialog.cpp b/src/start-chat-dialog.cpp
index e9ac1f8..c508c1e 100644
--- a/src/start-chat-dialog.cpp
+++ b/src/start-chat-dialog.cpp
@@ -11,8 +11,6 @@
 #include "start-chat-dialog.h"
 #include "ui_start-chat-dialog.h"
 
-using namespace std;
-
 StartChatDialog::StartChatDialog(QWidget *parent) 
   : QDialog(parent)
   , ui(new Ui::StartChatDialog)
@@ -31,7 +29,7 @@
 }
 
 void
-StartChatDialog::setChatroom(const string& chatroom)
+StartChatDialog::setChatroom(const std::string& chatroom)
 { 
   ui->chatroomInput->setText(QString::fromStdString(chatroom)); 
 }