Merge branch 'master' of git://github.com/melinath/philo

Merge branch 'master' of git://github.com/melinath/philo

* 'master' of git://github.com/melinath/philo:
  Added indices to all Attribute fields to improve lookup speed. Added related_lookup_fields to NodeAdmin for grappelli forward-compatibility.
  Tweaked LazyNode to handle trailing slashes. Corrected missing import in models/nodes.py.
  Corrected shipherd handling of the navigation_items related_name following commit 6ac457d4ac226a474e988dfb898682ae04a86eb0.
  Removed trailing_pathsep support from TreeManager.get_with_path. Set nodes to have URLs without a trailing slash, and set node_view to redirect node urls with a trailing slash to the same url, but without the slash. Resolves issue 75 completely.
  Added an abstract TargetURLModel to handle issues related to targeting a node, a node's subpaths, a url, or a reversable view. Addresses issue 79 and issue 76.
  Minor correction to LazyNode's use of subpath to avoid NameErrors.
  Minor cleanup to penfield.utils after get_absolute_url refactor.
  Refactored Node.get_absolute_url and related functions (such as MultiView.reverse) to use a new Node.construct_url function, which handles constructing any type of url involving a node or raises an appropriate error if this is not possible. Moved MultiView.reverse to View and merged View.get_subpath into it. Added APPEND_SLASH support to node_view, including support for resolving non-philo targets (resolves issue 75). Made urlpatterns for penfield and waldo MultiViews unambiguous. Altered LazyNode to always return a subpath of at least "/". Added handles_subpath methods to View and MultiView.
  Registered Tag as a value model.
  Corrected EntityAdminMetaclass handling of inherited vs. declared readonly_fields.
  Clarified error messages and docstrings in models/nodes.py. Removed an extraneous argument to MultiView.urlpatterns.
  Added navigation key to shipherd's has_navigation filter.