ISIS-356: injectXxx for injecting services.
ISIS-358: be able to delete non-versioned objects.
ISIS-357, ISIS-359: gracefully handle deleted objects, bulk actions must be no-arg.
ISIS-295: JDO validator flags unsupported annotations early.

Don't want to tackle @Aggregated entities just yet, but - to improve matters at least a little -
have implemented a MetaModelValidator that will flag up any use of @Aggregated (or @EmbeddedOnly)
and say that they are not supported by the JDO objectstore.
ISIS-360: about message shows version and other manifest attributes.