Binger-cn

Results 2 issues of Binger-cn

I was dealing with some log files of about 78G size. Even using fill=True, I got errors: ![image](https://user-images.githubusercontent.com/87395223/126255317-9a80f0ea-055f-45da-b844-58578bb0b302.png) IOError: Too many fields on line 104485: expected 20 but more are...

```vaex.from_arrays(k=[]).k.value_counts() ``` error: ~/miniconda3/lib/python3.9/site-packages/vaex/cpu.py in reduce(self, others) 212 for other in [self, *others]: 213 counters.extend([k for k in other.counters if k is not None]) --> 214 counter = counters[0] 215...