rm unfinished undo/redo engine (#757)

This resolves #757 (closed).

GUI/View/SampleDesigner/SampleEditorCommands.cpp

-//  ************************************************************************************************
-//
-//  BornAgain: simulate and fit reflection and scattering
-//
-//! @file      GUI/View/SampleDesigner/SampleEditorCommands.cpp
-//! @brief     Implements command classes for LayerOrientedSampleEditor
-//!
-//! @homepage  http://www.bornagainproject.org
-//! @license   GNU General Public License v3 or higher (see COPYING)
-//! @copyright Forschungszentrum Jülich GmbH 2021
-//! @authors   Scientific Computing Group at MLZ (see CITATION, AUTHORS)
-//
-//  ************************************************************************************************
-
-#include "GUI/View/SampleDesigner/SampleEditorCommands.h"
-#include "GUI/Model/Sample/LayerItem.h"
-#include "GUI/Model/Sample/SampleItem.h"
-#include "GUI/Support/XML/Backup.h"
-#include "GUI/View/SampleDesigner/SampleEditorController.h"
-#include "GUI/View/SampleDesigner/SampleForm.h"
-#include <utility>
-
-namespace {
-
-constexpr int COMMAND_ID_CHANGE_VALUE = 11;
-
-} // namespace
-
-CommandChangeValue::CommandChangeValue(const QString& label, SampleEditorController* ec,
-                                       double oldValue, double newValue, const QString& path,
-                                       QUndoCommand* parent /*= nullptr*/)
-    : QUndoCommand(parent)
-    , m_ec(ec)
-    , m_oldValue(oldValue)
-    , m_newValue(newValue)
-    , m_path(path)
-{
-    setText("change " + label + "\n");
-}
-
-int CommandChangeValue::id() const
-{
-    return COMMAND_ID_CHANGE_VALUE;
-}
-
-void CommandChangeValue::redo()
-{
-    if (m_isFirst)
-        m_isFirst = false;
-    else
-        m_ec->setDoubleFromUndo(m_newValue, m_path);
-}
-
-void CommandChangeValue::undo()
-{
-    m_ec->setDoubleFromUndo(m_oldValue, m_path);
-}