Hide orphans and add treeview style

[DBinaghi]

Hi.

I've added two new options to the plugin:

• hide orphan collections: a chance to hide the collection tree on Admin and Public side if the collection has neither parent nor children;
• treeview style: option to display the collections in a graphical, treeview style instead of the default unordered lists; the treeview can be forcely expanded when first appearing (useful for Collection Show pages, where the number of children is limited).

Regards.