Generate default impl for abstract function

[dhuebner]

Guice needs a default implementation to inject a class. But we can't use generate once approach or wait until user implements a class.

@ImplementedBy(AddOne.AddOneDummy.class)
public abstract class AddOne implements RosettaFunction {

	/**
	 * @param arg
	 * @param d
	 * @return out
	 */
	public FooDat evaluate(FooDat arg, Date d) {

		FooDat out = doEvaluate(arg, d).build();

		return out;
	}

	protected abstract FooDat.FooDatBuilder doEvaluate(FooDat arg, Date d);


	private static final class AddOneDummy extends AddOne {
		@Override
		protected FooDatBuilder doEvaluate(FooDat arg, Date d) {
			throw new UnsupportedOperationException();
		}
	}
}

[dhuebner]

Implementeed as part of #85