* glom/glom/libglom/document/document.[h|cc]:
	LayoutInfo: Do not bother storing the parent table here because
	these are all stored in a table-specific map anyway.
        * glom/glom/glom_document.dtd: Remove the mention of the
	parent_table attribute. The parent table node already specifies
	it.
        * glom/examples/*.glom: Resave these without the parent_table
	attributes.