- Backend-agnostic Cache module (Redis extracted from Database), opt-in
  rate limiting and API versioning middleware
- Real, DB-introspection-based orm:schema-diff and working relationship
  generation/loading (ManyToOne/OneToOne/OneToMany/ManyToMany)
- Repository::findBy()/findOneBy(), EntityManager::loadRelation()
- Docs rewritten as a Tutorial + Reference site, six new reference pages
- Source comment cleanup