Allow changing roughness height statistics in GUI

Now roughness has its own collapsible form which can be further extended.

Height statistics is a separate option there.

Resolves #1016 (closed)

GUI/View/Sample/LayerForm.cpp

@@ -112,7 +112,6 @@ LayerForm::LayerForm(QWidget* parent, LayerItem* layerItem, SampleEditorControll
                                                   "Used for Average Layer Material calculations \n"
                                                   "when corresponding simulation option is set."));
 
-    //    m_layout->addSelection(m_layer->roughnessSelection());
     m_layout->addRow(
         new RoughnessForm(this, m_layer->roughnessSelection(), m_layer->expandRoughness, m_ec));
     m_roughness_row = m_layout->rowCount() - 1;