Cannot np.delete from DataFrame?
I expected to be able to delete columns from a DataFrame using numpy, perhaps this is not a supported feature?

``` python
>>> import pandas
>>> import numpy as np

>>> a = np.random.randn(10, 5)
>>> print a
[[-0.91594461 -0.53053436 -0.85001444 -0.85449801 -0.43819574]
 [ 0.95329084 -0.20825167  0.04241911  0.2584316  -0.94726073]
 [ 0.77250977  0.43216287 -1.89856666 -0.81366952  1.28053613]
 [-0.3429547  -1.48068496 -0.03506405  1.21071247 -1.20183875]
 [-0.0370853  -0.31445352  0.06883009 -1.84456128  1.71605349]
 [ 1.17911771  0.39696818  0.07772257 -0.32094673  0.31172983]
 [-0.66329584  1.00713056 -2.08220188  0.5176764   0.44289719]
 [-0.95182981 -0.69766579 -0.82955209 -0.69828292  2.00791278]
 [ 0.99209185  0.13148193 -0.13022876  0.74503304  0.33384755]
 [-1.12040205 -1.45429834  1.12394894 -1.1043654   1.07285193]]

>>> np.delete(a, [1,2], axis=1)
array([[-0.91594461, -0.85449801, -0.43819574],
       [ 0.95329084,  0.2584316 , -0.94726073],
       [ 0.77250977, -0.81366952,  1.28053613],
       [-0.3429547 ,  1.21071247, -1.20183875],
       [-0.0370853 , -1.84456128,  1.71605349],
       [ 1.17911771, -0.32094673,  0.31172983],
       [-0.66329584,  0.5176764 ,  0.44289719],
       [-0.95182981, -0.69828292,  2.00791278],
       [ 0.99209185,  0.74503304,  0.33384755],
       [-1.12040205, -1.1043654 ,  1.07285193]])

>>> df = pandas.DataFrame(a)
>>> print df
          0         1         2         3         4
0 -0.915945 -0.530534 -0.850014 -0.854498 -0.438196
1  0.953291 -0.208252  0.042419  0.258432 -0.947261
2  0.772510  0.432163 -1.898567 -0.813670  1.280536
3 -0.342955 -1.480685 -0.035064  1.210712 -1.201839
4 -0.037085 -0.314454  0.068830 -1.844561  1.716053
5  1.179118  0.396968  0.077723 -0.320947  0.311730
6 -0.663296  1.007131 -2.082202  0.517676  0.442897
7 -0.951830 -0.697666 -0.829552 -0.698283  2.007913
8  0.992092  0.131482 -0.130229  0.745033  0.333848
9 -1.120402 -1.454298  1.123949 -1.104365  1.072852

>>> np.delete(df, [1,2], axis=1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/site-packages/numpy-1.7.0-py2.7-linux-x86_64.egg/numpy/lib/function_base.py", line 3505, in delete
    return wrap(new)
  File "/usr/lib/python2.7/site-packages/pandas-0.10.1-py2.7-linux-x86_64.egg/pandas/core/frame.py", line 1800, in __array_wrap__
    columns=self.columns, copy=False)
  File "/usr/lib/python2.7/site-packages/pandas-0.10.1-py2.7-linux-x86_64.egg/pandas/core/frame.py", line 404, in __init__
    copy=copy)
  File "/usr/lib/python2.7/site-packages/pandas-0.10.1-py2.7-linux-x86_64.egg/pandas/core/frame.py", line 550, in _init_ndarray
    block = make_block(values.T, columns, columns)
  File "/usr/lib/python2.7/site-packages/pandas-0.10.1-py2.7-linux-x86_64.egg/pandas/core/internals.py", line 483, in make_block
    return klass(values, items, ref_items, ndim=values.ndim)
  File "/usr/lib/python2.7/site-packages/pandas-0.10.1-py2.7-linux-x86_64.egg/pandas/core/internals.py", line 33, in __init__
    % (len(items), len(values)))
AssertionError: Wrong number of items passed (5 vs 3)
```
