- session.execute() will execute a Sequence object passed to

- session.execute() will execute a Sequence object passed to
  it (regression from 0.4).
- Removed the "raiseerror" keyword argument from object_mapper()
  and class_mapper().  These functions raise in all cases
  if the given class/instance is not mapped.
- Refined ExtensionCarrier to be itself a dict, removed
'methods' accessor
- moved identity_key tests to test/orm/utils.py
- some docstrings