Allowed breadcrumbs helper to be able to be registered loading its
dependencies and added a working example app to it.

@namusyaka I have a feeling we could rework the way the helper works;
I've never used it but after looking at it because of @Signum's issue
the fact that you can't really replace a breadcrumb but that you have to
delete and add it again doesn't feel right. Thoughts?

Fixes #28.