Part 3: Generators layout and generate stub rest resources

From GWT's javadoc:
> com.google.gwt.core.ext.IncrementalGenerator
> public abstract long getVersionId()
> Returns a version id for an IncrementalGenerator. It is used by the system to invalidate CachedGeneratorResult's that were generated by a different version of this generator. This is useful when new versions of a generator are developed, which might alter the structure of generated output, or alter semantics for cache reusability checking.
> It is the responsibility of the developer to maintain this version id consistently.
> Returns:
> a version id

So I think it should only be changed when rest-dispatch generators are updated. 140 -> 1.4.0