Entity / entities attributes - fixed save / delete behavior when set as dynamic

[adrians5j]

Normally in entity / entities attributes, certain save / delete processes must occur once the main entity is being saved / deleted. This is because links need to be validated and properly managed.

But, if entity / entities attributes are marked as dynamic, value is always returned by provided callback, eg.:

this.attr("revisions")
                .entities(Page)
                .setDynamic(() => {
                    return Page.find({ query: { parent: this.parent }, sort: { version: -1 } });
                });

Also, these cannot have value assigned.

So in these cases, when entity / entities attributes are dynamic, mentioned save / deleted processes must not occur at all.

[coveralls]

Coverage decreased (-0.07%) to 94.961% when pulling 1e1d49f on entity/dynamicEntityDeleteFix into b9f51bb on development.