Implement a replacement for the `add_footer` option of bullet

[westonganger]

It would be really awesome if we could imitate the add_footer option of bullet.

I understand that getting involved with the view side of things may not be a core concern.

If native support is not possible, I would love for the project to include a simple example implementation of how to add this to a project.

[charkost]

The add_footer option of bullet is indeed very useful. I will probably add it when i have some spare time. Thanks for the feedback!