DataFrameGroupBy.boxplot() should not relay to DataFrame.boxplot()

[lodagro]

matplotlib boxplot() does not create a new figure by default (as hist() does).
Since DataFrameGroupby.boxplot() relays boxplot to DataFrame.boxplot(), one ends up with one messy plot.
See screenshot
Either DataFrameGroupby.boxplot() should not relay to DataFrame.boxplot() and handle this or other option is to change behavior of DataFrame.boxplot() and open a new figure before calling matplotlib boxplot.

In [300]: tuples = [t for t in itertools.product(list('abcdefghijkl'), range(4))]

In [301]: index = pandas.MultiIndex.from_tuples(tuples, names=['lvl0', 'lvl1'])

In [302]: df = pandas.DataFrame(np.random.randn(len(index),5), columns=list('ABCDE'), index=index)

In [303]: grouped = df.groupby(level=1)

In [304]: grouped.boxplot()
Out[304]:
lvl1
0       {'medians': [<matplotlib.lines.Line2D object at 0
1       {'medians': [<matplotlib.lines.Line2D object at 0
2       {'medians': [<matplotlib.lines.Line2D object at 0
3       {'medians': [<matplotlib.lines.Line2D object at 0