BUG: setting a sparse column in a frame buggy
from [SO](http://stackoverflow.com/questions/25517342/adding-a-sparse-series-to-a-dense-dataframe-in-pandas)

thought this was well tested.....

```
df = pd.DataFrame({'c_1':['a', 'b', 'c'], 'n_1': [1., 2., 3.]})
df['new_column'] = pd.Series([0, 0, 1]).to_sparse(fill_value=0)
# AssertionError: Shape of new values must be compatible with manager shape
```
