This change fixes a couple of consistency issues in the navigation block.
At the same time it fixes it the CSS for the navigation block as it had
really degraded over the last years.
Notable points about this change:
* Fixed icon display by wrapping content in a span allowing columns to
be styled.
* Re-wrote the CSS entirely as it could be done much better.
* Fixed inconsistencies between the php and JS for rendering nodes.
892e21aadd