v1.3.2

• Handle extend_() and clear_() methods in unique trees. (48af44c, #12)
• Update default number of parents in unique_tree decorator. (daad126)
• Fix inconsistent handling of context in names(), ids(), keys(), values(), items(). (a83bf77)
• Removed automatic instance_cache clearing. (e00c454)
• Add get_{leaf,root}_objs to unique trees. (6acf0a9)
• Fix unique tree properties. (38caf9a)
• Change some signature docs for unique object trees. (f2b9dd6)
• Add get_first and get_last methods to UniqueObjectIndex. (439135e)