"Applying multiple functions at once" example from the docs broken
Using `agg` with a list of functions as parameter on a `groupby` object doesn't work as described:

```
df = DataFrame({'A' : ['foo', 'bar', 'foo', 'bar', 'foo', 'bar', 'foo', 'foo'],
                'B' : ['one', 'one', 'two', 'three', 'two', 'two', 'one', 'three'],
                'C' : randn(8), 'D' : randn(8)})
grouped = df.groupby('A')
grouped.agg([np.sum, np.mean, np.std])
```

leads to this (with 0.6.1 stable and master):

---

AssertionError                            Traceback (most recent call last)
/home/ilja/env/<ipython-input-11-f7f54864ac69> in <module>()
----> 1 grouped.agg([np.sum, np.mean, np.std])

/usr/lib/python2.7/site-packages/pandas/core/groupby.pyc in agg(self, func, _args, *_kwargs)
    295         See docstring for aggregate
    296         """
--> 297         return self.aggregate(func, _args, *_kwargs)
    298 
    299     def _get_names(self):

/usr/lib/python2.7/site-packages/pandas/core/groupby.pyc in aggregate(self, arg, _args, *_kwargs)
    954                 return self._python_agg_general(arg, _args, *_kwargs)
    955             else:
--> 956                 result = self._aggregate_generic(arg, _args, *_kwargs)
    957 
    958         if not self.as_index:

/usr/lib/python2.7/site-packages/pandas/core/groupby.pyc in _aggregate_generic(self, func, _args, *_kwargs)
    982                     result[name] = func(data, _args, *_kwargs)
    983             except Exception:
--> 984                 return self._aggregate_item_by_item(func, _args, *_kwargs)
    985         else:
    986             for name in self.indices:

/usr/lib/python2.7/site-packages/pandas/core/groupby.pyc in _aggregate_item_by_item(self, func, _args, *_kwargs)
   1027             result_columns = result_columns.drop(cannot_agg)
   1028 
-> 1029         return DataFrame(result, columns=result_columns)
   1030 
   1031     def _wrap_aggregated_output(self, output, mask):

/usr/lib/python2.7/site-packages/pandas/core/frame.pyc in **init**(self, data, index, columns, dtype, copy)
    191             mgr = self._init_mgr(data, index, columns, dtype=dtype, copy=copy)
    192         elif isinstance(data, dict):
--> 193             mgr = self._init_dict(data, index, columns, dtype=dtype)
    194         elif isinstance(data, ma.MaskedArray):
    195             mask = ma.getmaskarray(data)

/usr/lib/python2.7/site-packages/pandas/core/frame.pyc in _init_dict(self, data, index, columns, dtype)
    260 
    261         # consolidate for now

--> 262         mgr = BlockManager(blocks, axes)
    263         return mgr.consolidate()
    264 

/usr/lib/python2.7/site-packages/pandas/core/internals.pyc in **init**(self, blocks, axes, do_integrity_check)
    274 
    275         if do_integrity_check:
--> 276             self._verify_integrity()
    277 
    278     @property

/usr/lib/python2.7/site-packages/pandas/core/internals.pyc in _verify_integrity(self)
    353         mgr_shape = self.shape
    354         for block in self.blocks:
--> 355             assert(block.values.shape[1:] == mgr_shape[1:])
    356         tot_items = sum(len(x.items) for x in self.blocks)
    357         assert(len(self.items) == tot_items)

AssertionError: 
