"basename" is now "stem" (preferred by Guido)
PEP 454

* replace Snapshot.create() class method with take_snapshot() function
* get_traces() now returns a list instead of a dict (remove addresses)
* remove get_stats()
* unknown frames are now stored as ("<unknown>", 0) instead of (None, None)
* remove get_object_address()
* remove get_trace()
* remove add_inclusive_filter() and add_exclusive_filter() functions
* remove "address" key type from Snapshot.group_by()
PEP 454: cleanup
PEP 454: remove GroupedStats.timestamp/.traceback_limit attributes

various cleanup
Update PEP 456 to reflect the changes in features/pep-456