[NestedNode] #11 - PageRepository does not extend NestedNodeRepository + first refactoring to work with sections
[NestedNode] #11 - Add PageRepository::getAncestor(Page $page, $level = 0)
[NestedNode] #11 - Add PageRepository::getAncestors(Page $page, $depth = null, $includeNode = false)
[NestedNode] #11 - Add Page::setModified(\Datetime modified)