Changes to XmlElement if you do not use XSDs

In 9.0, if you directly instantiate the XMLElement class rather than use schemas (XSDs) to create Gosu types, there are required changes.

Your code must change usages of special property names that now appear with a dollar sign ($) prefix. To fix the compile errors, add the dollar sign prefix for the following XmlElement properties: $AttributeNames, $Children, $DeclaredNamespaces, $MixedContent, $Namespace, $NamespaceContext, $QName, $SimpleValue, $Text, $TypeData, and $TypeInstance.

For example, if your code with a compile error says obj.Text, change it to obj.$Text.