Improving breadcrumbs on notebooklist-open

The notebooklist buffer now has a funcitonal breadcrumb list at the top
of the page.
Revert "Missed a reference to ein2"

This reverts commit ddd00d122ffa0a0c2147a1f998c6f1dde323325f.
Revert "Renaming to ein2"

This reverts commit 029f72d46d55b37f2274329964bd2e07cf79ab63.
Revert "ein2 branding, update requirements"

This reverts commit c54b23de35bae03a5da128f5a579583fc783e0bc.