The following visitors are included:
* PathToRoot: find the path back to the tree's root node
* FindByPath: find the node specified by a path
* FindByUID: find the node with the same UID
* FindByNodeValue: find the node with the same node value
* BreadthFirstTraversal: implements a breadth-first traversal
* PostOrderTraversal: implements a post-order traversal
* PreOrderTraversal: implements a pre-order traversal
* LoadDirectoryTree: load a directory tree into a Tree::Simple hierarchy
* CreateDirectoryTree: create a set of directories and files from a
Tree::Simple hierarchy
* FromNestedArray: create a Tree::Simple hierarchy from nested arrays
* ToNestedArray: create a nested array construct from a Tree::Simple hierarchy
* Tree::Simple::Visitor::VariableDepthClone: clone parts of Tree hierarchies
* FromNestedHash: create a Tree::Simple hierarchy from nested hashes
* ToNestedHash: create a nested hash construct from a Tree::Simple hierarchy
* LoadClassHierarchy: create a Tree::Simple hierarchy which models the classes
inheritance heirarchy
* GetAllDescendents: return all the descendents recursively on down the
hierarchy
* Sort: implements a multi-level sort of a Tree::Simple heirarchy
