All directory node objects can have children
Given a child object get the complete path to it
Get a child node by it's ID.
List child nodes of this directory type item
Walk down a given sub-path as far as possible and retrieve the closest descendant FIXME: Find a better name for this function, maybe resolveDeepest
Get the separator string to place after my path but before then names of any child items when generating a child path string.
Walk down a given sub-path and retrieve a fully constructed descendant node.