API: sparse.cumsum should default to stats axis
xref #12810 

```
In [1]: sp = pd.SparseDataFrame([1, 2, 3])

In [2]: np.cumsum(sp)
ValueError: No axis named None for object type <class 'pandas.sparse.frame.SparseDataFrame'>

In [3]: np.cumsum(sp, axis=0)
Out[3]: 
     0
0  1.0
1  3.0
2  6.0

In [4]: np.cumsum(sp, axis=1)
Out[4]: 
     0
0  1.0
1  2.0
2  3.0
```
