Make message boxes more platform independent with a wrapper

Instead  of  using the  Qt  QMessageBox  class  directly a  new  class
MessageBox  (MessageBox.hpp)  has been  added  to  deal with  platform
independence issues like the title not being shown on Mac OS X.

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6861 ab8295b8-cf94-4d9e-aec4-7959e3be5d79

HelpTextWindow.cpp

@@ -3,11 +3,11 @@
 #include <QApplication>
 #include <QString>
 #include <QPalette>
-#include <QMessageBox>
 #include <QFile>
 #include <QTextStream>
 
 #include "qt_helpers.hpp"
+#include <MessageBox.hpp>
 
 HelpTextWindow::HelpTextWindow (QString const& title, QString const& file_name, QFont const& font, QWidget * parent)
   : QLabel {parent, Qt::WindowCloseButtonHint | Qt::WindowMinimizeButtonHint}
@@ -15,9 +15,9 @@ HelpTextWindow::HelpTextWindow (QString const& title, QString const& file_name,
   QFile source {file_name};
   if (!source.open (QIODevice::ReadOnly | QIODevice::Text))
     {
-      QMessageBox::warning (this, QApplication::applicationName ()
-                            , "Cannot open \"" + source.fileName ()
-                            + "\" for reading:" + source.errorString ());
+      MessageBox::warning_message (this, tr ("Help file error")
+                                   , tr ("Cannot open \"%1\" for reading").arg (source.fileName ())
+                                   , tr ("Error: %1").arg (source.errorString ()));
       return;
     }
   setText (QTextStream {&source}.readAll ());