Rename meta 'tag' property to 'tags' as its plural
Unify prototype (mother of all).

Proto is no longer function with it's prototype but simple plain object.
Logic reorder
Remove everyRelationDeep

It's for to complex case, that should eventually be solved with
forEachRelation and forEachItem
Move forEachRelation to relation/instance

Made proto/instance as main proto module
Optionally filter getPropertyNames result with tag