Add summary method as alternative to describe that gives quartiles similar to Pandas

In [4]: df.describe()
Out[4]:
       Unnamed: 0       displ         year         cyl         cty         hwy
count  234.000000  234.000000   234.000000  234.000000  234.000000  234.000000
mean   117.500000    3.471795  2003.500000    5.888889   16.858974   23.440171
std     67.694165    1.291959     4.509646    1.611534    4.255946    5.954643
min      1.000000    1.600000  1999.000000    4.000000    9.000000   12.000000
25%     59.250000    2.400000  1999.000000    4.000000   14.000000   18.000000
50%    117.500000    3.300000  2003.500000    6.000000   17.000000   24.000000
75%    175.750000    4.600000  2008.000000    8.000000   19.000000   27.000000
max    234.000000    7.000000  2008.000000    8.000000   35.000000   44.000000