This breaks the following code:

```python
class MyDjangoScssFilter(ScssFilter):
    compiler = MyDjangoScss()
```

I think that we don't need to control the charset from here, because we don't even keep track of the value of it here.  If somebody wants to change the charset of DjangoScss, they can do it like this:

```python
class MyDjangoScssFilter(ScssFilter):
    compiler = DjangoScss(charset='latin1')
```

What do you think?