The renderer and styles require changes to match the new behaviour
introduced by the modifications to tree.js and the JavaScript renderer.
The PHP renderer now closely matches the JavaScript one, and we now use
the aria-hidden attribute to determine the node state.
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.
The biggest change is that the navigation block has been converted to a proper YUI module.
The following are the other changes made at the same time:
* A loading icon is displayed when a branch is being loaded by AJAX.
* Fixed a bug where you could trigger multiple AJAX requests by rapidly clicking an unloaded branch.
* Fixed a bug where empty branches weren't being marked as such after a successful AJAX load.
* When docked the width of the blocks dock panel is now inspected an increased if required to try avoid horizontal scrolling.
* Removed the no longer needed inclusion of the YUI2 dom library from the navigation and settings block.
* Expandable nodes are now passed as JS data allowing the navigation JS to be initialised through block_navigation::get_required_javascript.
* AJAX is now focused around the branch in question rather than the tree in general.
* Expansion of branches is now delegated to the tree rather than being an individual event on all branches.
* Tidied up the code in general removing unneeded-unused parameters.
Navigation has now been re-ordered in accordance with http://docs.moodle.org/en/Development:Navigation_2.0_structure.
This has led to several changes in the way in which navigation is generated included API changes, most notably using the
navigation_nodes add method now returns the newly added node rather than the key.
At the same time the global_navigation_tree block has been renamed to navigation and settings_navigation_tree to settings.
Damyon Wiese