gui: Add label showing total number of preview pages

gui/mainwindow.cpp

@@ -465,6 +465,7 @@ void MainWindow::makePreviews(int page)
 	ui->spinPreviewPage->setMaximum(numpages);
 	targets = targets.mid(begin, end);
 
+	ui->lblTotalPreviewPagesCount->setText(QString::number(numpages));
 	ui->previewProcessBar->setMaximum(targets.count());
 	ui->previewProcessBar->setMinimum(0);
 	ui->previewProcessBar->setValue(0);

gui/mainwindow.ui

@@ -27,7 +27,7 @@
        <enum>QTabWidget::South</enum>
       </property>
       <property name="currentIndex">
-       <number>2</number>
+       <number>1</number>
       </property>
       <widget class="QWidget" name="resultsTab">
        <attribute name="title">
@@ -155,6 +155,13 @@
             </property>
            </widget>
           </item>
+          <item>
+           <widget class="QLabel" name="lblTotalPreviewPagesCount">
+            <property name="text">
+             <string/>
+            </property>
+           </widget>
+          </item>
           <item>
            <spacer name="horizontalSpacer">
             <property name="orientation">