intermittent segfault after take error
Was playing around and managed to get a segfault, in several versions.  It's a little intermittent, and it may have to do with how things are left after an error is encountered.  The same code without the the faulty take line doesn't crash for me.

``` python
>>> import pandas as pd, sys
>>> sys.version
'2.7.3 (default, Aug  1 2012, 05:16:07) \n[GCC 4.6.3]'
>>> pd.__version__
'0.11.0.dev-14a04dd'
>>> df = pd.DataFrame({'A': {1.0: 0.0, 2.0: 6.0, 3.0: 12.0}, 'C': {1.0: 2.0, 2.0: 8.0, 3.0: 14.0}, 'B': {1.0: 1.0, 2.0: 7.0, 3.0: 13.0}})
>>> df
    A   B   C
1   0   1   2
2   6   7   8
3  12  13  14
>>> 
>>> df.take(df.unstack())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/pandas-0.11.0.dev_14a04dd-py2.7-linux-i686.egg/pandas/core/frame.py", line 2951, in take
    new_index = self.index.take(indices)
  File "/usr/local/lib/python2.7/dist-packages/pandas-0.11.0.dev_14a04dd-py2.7-linux-i686.egg/pandas/core/index.py", line 416, in take
    taken = self.view(np.ndarray).take(indexer)
IndexError: index out of range for array
>>> df.unstack()
A  2     0
   2     6
   3    12
B  2     1
   2     7
   3    13
C  2     2
   2     8
   3    14
Dtype: float64
>>> df.take(df.unstack())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/pandas-0.11.0.dev_14a04dd-py2.7-linux-i686.egg/pandas/core/frame.py", line 2951, in take
    new_index = self.index.take(indices)
  File "/usr/local/lib/python2.7/dist-packages/pandas-0.11.0.dev_14a04dd-py2.7-linux-i686.egg/pandas/core/index.py", line 416, in take
    taken = self.view(np.ndarray).take(indexer)
IndexError: index out of range for array
>>> df.unstack()
Segmentation fault (core dumped)
```
