Removed duplications and Unused methods

Author: tegaidogun

include/ui/main_window.hpp

@@ -39,7 +39,6 @@ class MainWindow : public QMainWindow {
 
 private slots:
     void on_add_equation();
-    void on_equation_changed();
     void on_config_changed(const graph::GraphConfig& config);
     void on_remove_equation();
     void on_clear_all_equations();

src/ui/graph_widget.cpp

@@ -14,7 +14,6 @@
 #include <QString>
 #include <cmath>
 #include <QPixmap>
-#include <QPainter>
 
 namespace plot_genius {
 namespace ui {

src/ui/main_window.cpp

@@ -234,10 +234,6 @@ void MainWindow::on_add_equation() {
     }
 }
 
-void MainWindow::on_equation_changed() {
-    m_graph_widget->update_graph();
-}
-
 void MainWindow::on_remove_equation() {
     int row = m_equation_list->currentRow();
     if (row >= 0 && row < static_cast<int>(m_graph->get_equations().size())) {