Hide empty Taxonomy Terms

Updated patch -- please ignore 28 patch

Rerolled for 3.6

Changed termUsed and childTermUsed functions from private to protected.

Made childTermUsed accept vocabulary parameter.

Makes correction on
taxonomy_menu-hide_empty_taxonomy_menu-2884294-32.patch

I activated and configured the taxonomy_entity_index module and it hid the taxonomy entries without related nodes.
I added a new node in an empty term, but the menu item remained hidden.

I've refactored the code from the last patch and improved the work with hiding parent when child terms are used.

The patch above didn't apply. Here is correct.