doctrine/doctrine2 — pull request #896 by holtkamp (2014-01-05 14:36:23+00:00)
Title: Ensure <cascade/> elements preceed <join-columns/>

When converting annotations based metadata to XML, the position of the `````` elements in the generated files resulted in XSD validation errors caused by the definitions of the association ComplexTypes:
- https://github.com/doctrine/doctrine2/blob/master/doctrine-mapping.xsd#L463
- https://github.com/doctrine/doctrine2/blob/master/doctrine-mapping.xsd#L482
- https://github.com/doctrine/doctrine2/blob/master/doctrine-mapping.xsd#L495
- https://github.com/doctrine/doctrine2/blob/master/doctrine-mapping.xsd#L517

Since changing the XSD might result in validation problems in existing mappings, changing the XmlExporter seems a better approach.

Note that the `````` element is not yet generated by the XmlExporter, but according to the XML Schema, it should precede the `````` element.