[Qt] add utilitydialog.cpp/h and helpmessage class

- adds a nice and well formated dialog, which displays our -? help message
  (all options/paramaters)
- moves aboutdialog.cpp/h to the new utilitydialog
- move GUI shutdown window to utilitydialog

src/qt/utilitydialog.h

@@ -0,0 +1,69 @@
+// Copyright (c) 2011-2014 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef UTILITYDIALOG_H
+#define UTILITYDIALOG_H
+
+#include <QDialog>
+#include <QObject>
+
+class BitcoinGUI;
+class ClientModel;
+
+namespace Ui {
+    class AboutDialog;
+    class HelpMessageDialog;
+}
+
+/** "About" dialog box */
+class AboutDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit AboutDialog(QWidget *parent);
+    ~AboutDialog();
+
+    void setModel(ClientModel *model);
+
+private:
+    Ui::AboutDialog *ui;
+
+private slots:
+    void on_buttonBox_accepted();
+};
+
+/** "Help message" dialog box */
+class HelpMessageDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit HelpMessageDialog(QWidget *parent);
+    ~HelpMessageDialog();
+
+    void printToConsole();
+    void showOrPrint();
+
+private:
+    Ui::HelpMessageDialog *ui;
+    QString header;
+    QString coreOptions;
+    QString uiOptions;
+
+private slots:
+    void on_okButton_accepted();
+};
+
+
+/** "Shutdown" window */
+class ShutdownWindow : public QObject
+{
+    Q_OBJECT
+
+public:
+    static void showShutdownWindow(BitcoinGUI *window);
+};
+
+#endif // UTILITYDIALOG_H