Material: Continued Material enahncements

Continues the work of the material subsystem improvements.

Several important items are included in this merge. In terms of new
capabilities, this merge adds List and MultiLineString as valid
property types, complete with editing dialogs. This will help with
backwards compatibility for external workbenches, such as Render.

Stability has been a big focus. New unit tests help to verify features
work as expected. Bugs have been fixed and crashes avoided.

Material cards have had a renaming to their tree structure. For
example, 'StandardMeterials' is redundant, so this was renamed to
'Standard'. The cards themselves are more compliant fully passing the
yamllint tests.

More soon.

src/Mod/Material/Gui/Array2D.cpp

@@ -99,7 +99,7 @@ void Array2D::setupDefault()
 
     try {
         const Materials::MaterialProperty& column1 = _property->getColumn(0);
-        QString label = tr("Default ") + column1.getName();
+        QString label(tr("Default ") + column1.getName());
         ui->labelDefault->setText(label);
         if (column1.getPropertyType() == QString::fromStdString("Quantity")) {
             ui->editDefault->setMinimum(std::numeric_limits<double>::min());