message: Remove boost dependency
  Instead of using boost::lexical_cast we can just use std::to_string
diff: #include "walletmodel.h"
  #include <QLineEdit>
  #include <QMessageBox>
  -#include <boost/lexical_cast.hpp>
  MultiSendDialog::MultiSendDialog(QWidget* parent) : QDialog(parent, Qt::WindowSystemMenuHint | Qt::WindowTitleHint | Qt::WindowCloseButtonHint),
  @@ -91,7 +90,7 @@ void MultiSendDialog::on_viewButton_clicked()
  }
  strMultiSendPrint += pMultiSend.first.c_str();
  strMultiSendPrint += " - ";
  - strMultiSendPrint += boost::lexical_cast<string>(pMultiSend.second);
  + strMultiSendPrint += std::to_string(pMultiSend.second);
  strMultiSendPrint += "% \n";
  }
  ui->message->setProperty("status", "ok");
  @@ -140,7 +139,7 @@ void MultiSendDialog::on_addButton_clicked()
  pMultiSend = pwalletMain->vMultiSend[i];
  strMultiSendPrint += pMultiSend.first.c_str();
  strMultiSendPrint += " - ";
  - strMultiSendPrint += boost::lexical_cast<string>(pMultiSend.second);
  + strMultiSendPrint += std::to_string(pMultiSend.second);
  strMultiSendPrint += "% \n";
  }
  