xsd-fu: Generate sources at build time

The existing sources generated with xsd-fu by hand, and then committed into git have been removed, and are generated on the fly.  Some things which might need checking:

- everything is properly cleaned
- remaining sources in components/ome-xml/src/ome/xml/model are OK to remain
- source generating targets at the toplevel appear to be called more than once during a build; maybe the dependencies could be declared better, or the ant equivalent of make stamp files need using to prevent multiple invocations.
- as yet does not include maven support; the ant build works and has also been tested on Windows