UL and OL in series are parsed as one list

Basically `markup-it`, `marked` and `kramed` are failing to parse the following snippet as GitHub:

```
1. First point.
2. Second point.
3. Third point.

- Bullet point.
- Another bullet point.
```

`markup-it` parses it as:

```
1. First point.
2. Second point.
3. Third point.
4. Bullet point.
5. Another bullet point.
```

Related: GitbookIO/feedback#272
