Added serialVerionUID constants.

Triangle.Compiler/src/main/java/Triangle/SyntacticAnalyzer/SyntaxError.java

@@ -16,6 +16,8 @@ package Triangle.SyntacticAnalyzer;
 
 class SyntaxError extends Exception {
 
+  private static final long serialVersionUID = -5280306336102766860L;
+
 SyntaxError() {
     super();
   }

Triangle.Compiler/src/main/java/Triangle/TreeDrawer/DrawerFrame.java

@@ -25,6 +25,11 @@ import javax.swing.JPanel;
 import javax.swing.JScrollPane;
 
 class DrawerFrame extends JFrame {
+  /**
+	 *
+	 */
+	private static final long serialVersionUID = -3650404598416929282L;
+
 public DrawerFrame(JPanel panel) {
     setSize(300, 200);
     Toolkit tk = Toolkit.getDefaultToolkit();

Triangle.Compiler/src/main/java/Triangle/TreeDrawer/DrawerPanel.java

@@ -20,6 +20,10 @@ import java.awt.Graphics;
 import javax.swing.JPanel;
 
 class DrawerPanel extends JPanel {
+  /**
+	 *
+	 */
+	private static final long serialVersionUID = 565914745506889669L;
 private Drawer drawer;
 
   public DrawerPanel(Drawer drawer) {