Mouse-over in DataFrame plot shows wrong dates
In a new IPython Notebook session:

import pandas as pd
import numpy as np
%matplotlib
dt_rng = pd.date_range(start='2014-01-01', end='2014-01-31', freq='1min')
df = pd.DataFrame(np.random.randn(len(dt_rng)), index=dt_rng)
ax = df.plot()

The DataFrame is plotted correctly. However, a mouse-over shows wrong dates starting in the year 1970. The axis-labelling is correct.

Editing the format_coord function shows something interesting:

ax.format_coord = lambda x,y: "{} {}".format(x,y)

231422240.[....] and so on. This float value obviously isn't parsed correctly. Any ideas?

Thanks for making pandas so great and best regards!
