API: add level kwarg for Series.any/.all
It appears that Series' `s.any` and `s.all` methods miss level kwargs, unlike their statistical counterparts like `s.sum`:

``` python
In [4]: s = pd.Series([0,1,2], index=[0,0,1])

In [5]: s.sum(level=0)
Out[5]: 
0    1
1    2
dtype: int64

In [6]: s.prod(level=0)
Out[6]: 
0    0
1    2
dtype: int64

In [7]: s.any(level=0)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-7-1d8c43752bc9> in <module>()
----> 1 s.any(level=0)

/home/immerrr/sources/pandas/pandas/core/series.pyc in f(self, *args, **kwargs)
     74     @Appender(func.__doc__)
     75     def f(self, *args, **kwargs):
---> 76         result = func(self.values, *args, **kwargs)
     77         if isinstance(result, (pa.Array, Series)) and result.ndim == 0:
     78             # return NumPy type

TypeError: _any() got an unexpected keyword argument 'level'

In [8]: s.all(level=0)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-8-bca0491001a6> in <module>()
----> 1 s.all(level=0)

/home/immerrr/sources/pandas/pandas/core/series.pyc in f(self, *args, **kwargs)
     74     @Appender(func.__doc__)
     75     def f(self, *args, **kwargs):
---> 76         result = func(self.values, *args, **kwargs)
     77         if isinstance(result, (pa.Array, Series)) and result.ndim == 0:
     78             # return NumPy type

TypeError: _all() got an unexpected keyword argument 'level'

```

Frames have those and I think so should series. Maybe, there are more reduction methods that I know not of that also miss those...
