Package for working with bread crumb components.

Bread crumbs provide a means to track certain history of client actions. Bread crumbs are typically rendered as a list of links, and are useful when users 'dig deeper' into the site structure so that they can find their way back again and have a notion of where they currently are.

Bread crumbs in the original sense just represent where people are in a site hierarchy. For example, when browsing a product site, bread crumbs could look like this:

               Home > Products & Solutions > Hardware > Desktop Systems

or

               World > Europe > The Netherlands > Utrecht

These items would be rendered as links to the corresponding site location.

The central interface of this package is `IBreadCrumbModel`, which models the concept of bread crumbs. The main implementation of bread crumbs is the `BreadCrumbBar`, which is a Wicket component that renders the bread crumbs and an implementation of `IBreadCrumbModel` in one.