DateTimeBase.setCentury() should check for year = 0

The method org.exolab.castor.types.DateTimeBase.setCentury() should have the same checking as setYear() to avoid setting century and year to 0:

else if ( (_year ==0) && (century==0))

Otherwise you can do:

org.exolab.castor.types.Date dob = new org.exolab.castor.types.Date();
dob.setCentury((short) 1);
dob.setYear((short) 0);
dob.setCentury((short) 0); // no exception here

and if you marshall, you get an "0000-MM-DD" in your XML for date, which is (currently) forbidden (according to http://www.w3.org/TR/xmlschema-2/ chapter 3.2.7).

If you then unmarshall, you get a (correct) error message for the parser.

The attached eclipse project showing the error, is compiled with castor 1.0.1, but the problem is also in 1.0.3.