directly selecting a node with submenu

[stfl]

A -> A.1 -> A.2

Selecting a menu item with a submenu (A) will always call _process_breadcrums() on all submenu items (A.1, A.2) If non of the submenu items is selected, the parent node is also not selected.

Selecting A.1 will work and select A. Directly selecting A will not mark A as selcted, as neither A.1 nor A.2 are selected.

fixes https://github.com/LaLogiaDePython/django-menu-generator/issues/16