Breadcrumbs could not handle multiple paths to access a particular state.

**Description of issue**: If we have a state **loggedIn.view1.service1** which could also be accessed by a path **loggedIn->view2->service1**, then the breadcrumbs would only be based on **loggedIn->view1->service1**.
Although we can access service1 from view1, but we need to register a state for **loggedIn.view2.service1**. Since ngbreadcrumb.js is using _currentState.parent_ so it always look for a parent instead of previous state.

Start by reading ngbreadcrumb.js, especially how it uses currentState.parent when constructing breadcrumbs. Reproduce the loggedIn.view1.service1 and loggedIn.view2.service1 navigation paths, then verify that the breadcrumb trail reflects the path actually used to reach service1 rather than only the registered parent hierarchy.

Written by the indexing model from the issue text.