Strange error message when summing datetime64 and datetime.time column
You get `TypeError: Argument 'values' has incorrect type (expected numpy.ndarray, got Series)`:

```
In [29]: df = pd.DataFrame({'date':pd.date_range('2012-01-01', periods=3), 'time':[datetime.time(i, i, i) for i in range(3)]})

In [30]: df
Out[30]:
        date      time
0 2012-01-01  00:00:00
1 2012-01-02  01:01:01
2 2012-01-03  02:02:02

In [31]: df['date'] + df['time']
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-31-5101228e303e> in <module>()
----> 1 df['date'] + df['time']

C:\Anaconda\lib\site-packages\pandas\core\ops.pyc in wrapper(left, right, name)
    491             return NotImplemented
    492
--> 493         time_converted = _TimeOp.maybe_convert_for_time_op(left, right,
name)
    494
    495         if time_converted is None:

C:\Anaconda\lib\site-packages\pandas\core\ops.pyc in maybe_convert_for_time_op(c
ls, left, right, name)
    455         if name.startswith('__r'):
    456             name = "__" + name[3:]
--> 457         return cls(left, right, name)
    458
    459

C:\Anaconda\lib\site-packages\pandas\core\ops.pyc in __init__(self, left, right,
 name)
    272         self.right = right
    273         lvalues = self._convert_to_array(left, name=name)
--> 274         rvalues = self._convert_to_array(right, name=name, other=lvalues
)
    275
    276         self.is_timedelta_lhs = com.is_timedelta64_dtype(left)

C:\Anaconda\lib\site-packages\pandas\core\ops.pyc in _convert_to_array(self, val
ues, name, other)
    354             elif not (isinstance(values, (np.ndarray, pd.Series)) and
    355                       com.is_datetime64_dtype(values)):
--> 356                 values = tslib.array_to_datetime(values)
    357         elif inferred_type in ('timedelta', 'timedelta64'):
    358             # have a timedelta, convert to to ns here

TypeError: Argument 'values' has incorrect type (expected numpy.ndarray, got Series)
```
