Wrong score in Partial Ratio

Hi,

I am using 1.4.0, this gives a wrong results with partial ratio:

```
FuzzySearch.partialRatio("ttttttttt virtuale ggggggggggggvo zizzrztuta mmmmmle", "virtuale"); 
```

the score is `50`, it has to be `100` imho.

The python version returns `100` too:

```
>>> fuzz.partial_ratio("ttttttttt virtuale ggggggggggggvo zizzrztuta mmmmmle", "virtuale")
100
```

Thanks for the help