Add about dialog to File menu of the connection manager.

Make the contents of the dialog more accurate and include a link to the releasenotes file.

pglab/About.cpp

@@ -0,0 +1,23 @@
+#include "About.h"
+#include <QCoreApplication>
+#include <QMessageBox>
+#include <QString>
+
+void ShowAboutDialog(QWidget *parent)
+{
+    QString pgLabVersionString = "0.2";
+    QString releaseNotesUrl = "file:///" + QCoreApplication::applicationDirPath() + "\\releasenotes.html";
+    QString year = QString::fromLatin1(__DATE__, 11).right(4);
+    QMessageBox::about(parent, "pgLab " + pgLabVersionString, QMessageBox::tr(
+              "<h1>Version %3</h1>"
+              "<p><a href=\"%2\">Releasenotes</a></p>"
+              "<p>Copyrights 2016-%1, Eelke Klein, All Rights Reserved.</p>"
+              "<p>The program is provided AS IS with NO WARRANTY OF ANY KIND, "
+              "INCLUDING THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS "
+              "FOR A PARTICULAR PURPOSE.</p>"
+              "<p>This program is dynamically linked with Qt " QT_VERSION_STR " Copyrights "
+              "the Qt Company Ltd. https://www.qt.io/licensing/.</p>"
+              "<p>Some icons by <a href=\"https://icons8.com\">Icons8</a> and others by <a href=\"http://www.fatcow.com/free-icons\">fatcow</a> provided under Creative Commons "
+              "attribution 3.0 license.</p>"
+              ).arg(year).arg(releaseNotesUrl).arg(pgLabVersionString));
+}