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

widegraph.cpp

@@ -4,13 +4,13 @@
 #include "ui_widegraph.h"
 #include "commons.h"
 #include "Configuration.hpp"
+#include "MessageBox.hpp"
 #include "moc_widegraph.cpp"
 
-static float swide[MAX_SCREENSIZE];
-
 namespace
 {
   auto user_defined = QObject::tr ("User Defined");
+  float swide[MAX_SCREENSIZE];
 }
 
 WideGraph::WideGraph(QSettings * settings, QWidget *parent) :
@@ -367,9 +367,7 @@ void WideGraph::readPalette ()                                   //readPalette
     }
   catch (std::exception const& e)
     {
-      QMessageBox msgBox0;
-      msgBox0.setText(e.what());
-      msgBox0.exec();
+      MessageBox::warning_message (this, tr ("Read Palette"), e.what ());
     }
 }
 
@@ -412,9 +410,7 @@ void WideGraph::on_adjust_palette_push_button_clicked (bool)   //Adjust Palette
     }
   catch (std::exception const& e)
     {
-      QMessageBox msgBox0;
-      msgBox0.setText(e.what());
-      msgBox0.exec();
+      MessageBox::warning_message (this, tr ("Read Palette"), e.what ());
     }
 }