Add invoke(), for_each() and for_each_right()

Nope, it's for methods like .sort() that return None, but Lodash still appends the sorted list. The first test shows the issue:

```
>>> item = [5, 1, 7]
>>> getattr(item, 'sort')()  # None
>>> lst.append(item)
>>> lst
[[1, 5, 7]]
```