plotting 3x3 scatter-matrix: missing labels
I create a pandas scatter-matrix usng the following code:

``` python
import numpy as np
import pandas as pd

a = np.random.normal(1, 3, 100)
b = np.random.normal(3, 1, 100)
c = np.random.normal(2, 2, 100)

df = pd.DataFrame({'A':a,'B':b,'C':c})
pd.scatter_matrix(df, diagonal='kde')
```

This result in the following scatter-matrix:
![scatter-matrix-3](https://f.cloud.github.com/assets/1548156/98709/56df06f8-672f-11e2-8471-3011933d7cc1.png)

The first row has no ytick labels, the 3th column no xtick labels, the 3th item 'C' is not labeled.

Any idea how to complete this plot with the missing labels ?
