BUG: Empty DataFrame.style.render raises IndexError
#### Code Sample, a copy-pastable example if possible

```python
In [6]: pd.DataFrame().style.render()
---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-6-345e1b37074e> in <module>()
----> 1 pd.DataFrame().style.render()

/Users/taugspurger/Envs/dask-dev/lib/python3.6/site-packages/pandas/formats/style.py in render(self)
    416         """
    417         self._compute()
--> 418         d = self._translate()
    419         # filter out empty styles, every cell will have a class
    420         # but the list of props may just be [['', '']].

/Users/taugspurger/Envs/dask-dev/lib/python3.6/site-packages/pandas/formats/style.py in _translate(self)
    252                            "is_visible": True})
    253
--> 254             for c in range(len(clabels[0])):
    255                 cs = [COL_HEADING_CLASS, "level%s" % r, "col%s" % c]
    256                 cs.extend(cell_context.get(

IndexError: list index out of range
```
#### Problem description

We assume that there's at least one column (and probably row)

#### Expected Output

Should match the output of an empty DataFrame in the notebook