Arithmetic Broadcasting
Okay, so the following "new" syntax is fine.

import pandas as pd
import random as randy
df = pd.DataFrame({'A': range(1000), 'B': randy.sample(range(1000),1000)},\
                  index=randy.sample(pd.date_range('2013-02-01 09:00:00.000000',periods=1e6,freq='U'),1000)).sort_index()

df.sub(df['A'],axis=0)

But, at some point, this has been broken:

df - df['A']

When did this overload change?
