Data Frame division
I am seeing the following behavior when dividing dataframes A and B below.  It seems there is cross divisions between common indexes as in Out[268] below.  I am hoping for Out[269].
Is the former the intended behavior?

![image](https://f.cloud.github.com/assets/4120749/365315/002a11c6-a240-11e2-8411-4e7bac6a4d47.png)
