CURATOR-33 recursive TreeCache recipe

is this the same behavior as the `PathChildrenCache` (e.g. events fire during initialization, and then initialization marks that the tree has been built?)

I can see arguments for structuring this both ways, but it's easy enough to compose the path children cache kind of behavior if you need to just block for the initialized event. In either case, I think the doc should be more clear about what's going on here. (And in `PathChildrenCache`)