KeyError: 'trait_names' in py3k
When tab completing in ipython notebook on `pd.options...`, nothing shows up, and on the backend (in iterm) I see a `KeyError: 'trait_names'`, with a longer traceback.

pd.version.version == '0.12.0'
python version == 3.3.2
IPython.version_info == (2, 0, 0, 'dev')

Pandas is latest from pip, and ipython is latest from git. It may be an IPython problem.

Traceback [here](https://gist.github.com/d10genes/6936334).
