Change the way children work

[kytta]

Currently, using submenu is quite confusing. It works fine for two menu levels, but there are problems using it with more levels (see also #47).

I wonder, if changing the underlying structure of the tags might help. I imagine a linked-list kind of deal, which itself describes a path in the menu tree from the root to the current active page. This way, one could search and/or iterate the whole way from the root to the page, making working with children AND grandchildren easy.

I will try to jot down some idea of how this should work :)