lib: disable repeated extent TODO message
lib/tree: use more compact key notation
lib/tree: copy bugfix from leaf_split_post to branch_split_post
lib/tree: take index instead of item_ref in leaf_data_ptr
lib/tree: fix unmap problem with tree_retrieve
lib/tree: better handle changed parent addr in node split
lib/tree: only call memmove in leaf_shift_* if necessary
redo: remove targets for tree utility
test: add nice rand functions; create new tree test with permuted IDs