Added NodeOverrideInlineFormSet to clean up admin editing of node overrides by only displaying overrides where both the override's parent and the override's child__parent are the current instance. Cleaned up migrations by merging the change of NodeNavigationOverride.parent to allow null into the original migration that created NodeNavigationOverrides. Made navigation include the root node in the top-level navigation... not sure this is the correct way to handle things. Added navigation-generating template tag.