added 'add new label' support

YACReaderLibrary/add_label_dialog.h

@@ -3,16 +3,22 @@
 
 #include <QtWidgets>
 
+#include "yacreader_global.h"
+
 class AddLabelDialog : public QDialog
 {
     Q_OBJECT
 public:
     explicit AddLabelDialog(QWidget *parent = 0);
-
+    YACReader::LabelColors selectedColor();
+    QString name();
 signals:
 
 public slots:
-    void open();
+    int exec();
+
+protected slots:
+    void validateName(const QString & name);
 
 protected:
     QLineEdit * edit;