gui: add basic gui code.

Gui/Control/CompareControl.h

@@ -0,0 +1,22 @@
+#ifndef COMPARECONTROL_H
+#define COMPARECONTROL_H
+
+#include <QWidget>
+
+namespace Ui {
+class Compare;
+}
+
+class Compare : public QWidget
+{
+    Q_OBJECT
+
+public:
+    explicit Compare(QWidget *parent = nullptr);
+    ~Compare();
+
+private:
+    Ui::Compare *ui;
+};
+
+#endif // COMPARECONTROL_H