Add leaf count to trees.
Document API, fix zero master tree.
Go back to simple tree representation to ease recursive processing in master-tree.
Going back to simple tree represented as node maps.
Implement find in master tree.
Rewrite simpler find-tree using map and reduce.
Use set/union in tree lattice operations to iterate over union of keys.
Fix error in find-tree.
Implement find-insert-tree.
Clean obsolete comment.
Implement tree store.
Unit test tree-store.
Unit test tree-store.
Test bracn-join on empty paths list.
Implement orthogonality predicate on trees.
Merge origin/implicit-lattice into implicit-lattice
Add orthogonality unit test case.
Less onerous unit test.
Represent trees in the master tree as sets of maximal paths in reverse, with structural sharing.