attributes line `wrap_links` not configurable on the library level

- Version by `html2text --version`
```html2text==2019.9.26```

In the current version of html2text, if one tries to use the library through `html2text` function or `HTML2Text` class, there's no way to specify variables such as `wrap_links` for the program. It would be preferable if the class `HTML2Text` allowed configuration regardless of the cli usage. Currently, the package is not usable as a library.