pd.crosstab's handling of categorical variables
#### Code Sample

```python
kyle = pd.DataFrame({'foo':np.random.randint(0,100,100),'boo':np.random.randint(0,100,100)})
kyle.loc[:,'fooCut'] = pd.qcut(kyle.loc[:,'foo'], np.arange(0,1.1,.1))
kyle.loc[:,'booCut'] = pd.qcut(kyle.loc[:,'boo'], np.arange(0,1.1,.1))

print(kyle.footCut.dtype)

pd.crosstab(kyle.fooCut,kyle.booCut)
```
#### Problem description

According to the documentation and previous versions of Pandas, `pd.Crosstab` handled categorical variables returned by `pd.qcut` but in version .24.2 pd.crosstab throws a TypeError even though both columns agree with the dtype presented in the [documentation](https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.crosstab.html)
