add useful node repository helper functions
fix for wrong highlighting in admin tree / page title / breadcrumbs...
entity interface added
Merge pull request #60 from wimvds/feature/add-entity-interface

entity interface added
Merge pull request #61 from wimvds/feature/refactor-admin-menu

fix for wrong highlighting in admin tree / page title / breadcrumbs...
Merge pull request #62 from wimvds/feature/add-node-repository-helper-functions

add useful node repository helper functions