pydata/pandas — pull request #5084 by jtratner (2013-10-02 12:01:23+00:00)
Title: CLN: Remove internal classes from MultiIndex pickle.

FrozenNDArray had made it into the MI pickle. No reason to do that and just
complicates pickle compat going forward. Now they just output ndarray
instead (which also avoids the unnecessary nested pickle previously
occurring).

Fixes #5076.