Fix remnant from previous commit.
Cleanup of MenuActiveTrail + add docs (ported from Wim's patch).
Remove all static caching from MenuLinkTree.
Remove all other caching from MenuLinkTree.
Remove buildPageData() and buildAllData(); use buildTree() instead, in combination with newly added buildPageDataTreeParameters() and buildAllDataTreeParameters().
Actually remove buildPageData().
s/buildTree/build/, s/buildRenderTree/render/
Removed the unused MenuLinkTree::defaults.