Better fxml: static properties should be attributes

[Bill van Melle <billvm@…>]

These days fxgraph is producing fairly natural fxml, except when it comes to static properties. Instead of

<VBox alignment="top_center"> 
    ... 
    <GridPane.rowIndex>1</GridPane.rowIndex>
    <GridPane.columnIndex>0</GridPane.columnIndex>
    <GridPane.columnSpan>2</GridPane.columnSpan>
</VBox>

I want to see

<VBox alignment="top_center" GridPane.rowIndex="1" GridPane.columnIndex="0" GridPane.columnSpan="2">
    ...
</VBox>

This will make it much nicer if I want to share fxml with someone who's not using e(fx)clipse.