Cleaned up undo manager for context editor. Logically this should work

now but the table is one bunch of crap…so it does not react to context
changes. Because there are that much issues open regarding the context
editor and my decision of a redesign I will tackle it all together in
time. See #33, #42, #43, #116

src/main/java/fcatools/conexpng/gui/contexteditor/ContextEditorUndoManager.java

@@ -32,30 +32,28 @@ public ContextEditorUndoManager(Conf conf) {
      * UndoableEdit.
      */
     public void makeRedoable() {
+        final Conf curConf = conf.copy(conf);
+        final Conf lastConf = conf.copy(conf.lastConf);
         if (!undoRedoInProgress) {
             UndoableEdit undoableEdit = new AbstractUndoableEdit() {
                 private static final long serialVersionUID = -4461145596327911434L;
-                final Conf curConf = conf.copy(conf);
-                final Conf lastConf = conf.copy(conf.lastConf);
 
-                // Method that is called when we must redo the undone action
                 public void redo() throws javax.swing.undo.CannotRedoException {
                     super.redo();
-                    conf.context = curConf.context;
                     undoRedoInProgress = true;
-                    conf.newContext(conf.context);
+                    conf.newContext(curConf.context);
                     undoRedoInProgress = false;
+                    // change undo/redo button state
                     MainToolbar.getRedoButton().setEnabled(canRedo());
                     MainToolbar.getUndoButton().setEnabled(canUndo());
                 }
 
                 public void undo() throws javax.swing.undo.CannotUndoException {
                     super.undo();
-                    conf.context = lastConf.context;
-
                     undoRedoInProgress = true;
-                    conf.newContext(conf.context);
+                    conf.newContext(lastConf.context);
                     undoRedoInProgress = false;
+                    // change undo/redo button state
                     MainToolbar.getRedoButton().setEnabled(canRedo());
                     MainToolbar.getUndoButton().setEnabled(canUndo());
                 }
@@ -67,7 +65,5 @@ public void undo() throws javax.swing.undo.CannotUndoException {
             MainToolbar.getRedoButton().setEnabled(canRedo());
             MainToolbar.getUndoButton().setEnabled(canUndo());
         }
-        conf.lastConf = conf.copy(conf);
-
     }
 }