close server when clicking on back button

src/gui/DownloadSelectionGen.java

@@ -134,6 +134,8 @@ public class DownloadSelectionGen extends javax.swing.JPanel {
 
 					/** Actions to initiate when button "Back" is initiate */
 					private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
+							smudp.setStop();
+							smtcp.setStop();
 							ArgumentsGen a = new ArgumentsGen();
 							JFrame topFrame = (JFrame) SwingUtilities.getWindowAncestor(this);
 							topFrame.add(a);