Convert xsd:complexType with mixed content and no element children to text

I've made a change to the xs:element template because it was failing on the Jasper Reports schema.  

A complexType with @mixed='true' allows text interspersed with the elements
that are legal for it, but if there are no elements, that leaves us with
just text; thus it is equivalent to plain text.

I hope this will be useful.

Thanks.

Ed