Each entry should have at least 'url' and 'title'
keys and may also have 'sub' key containing the children of this entry. Note that
keys in the entry arrays serve as node identifiers and should be unique.
The menu entries can also contain custom keys. If such keys are present, then they will be used by renderers in creating the output (this usually means that the content of such a key will be assigned to the template placeholder with the same name).
Supported output modes
HTML_Menu supports five output modes: 'tree' (default), 'rows', 'urhere', 'prevnext' and 'sitemap'.
Lets use the array defined above as menu structure assuming that element 'Menu item 1.2' is currently active and try each menu type.
'tree'
This type of the menu mostly follows the internal structure of the menu hash.
Different levels of the menu are marked by indentation, only the elements leading to the active item
or immediately following it are shown.