Bump libertree-model-rb .
Bump factory_girl and dependencies.
Introduce @forest in tests .
Unnest some inner spec contexts that should not be nested.
Bump rspec.
Added Libertree::Server#in_a_forest? .
Return "UNRECOGNIZED SERVER" code when requester is not in any forest that the local server is a member of.
It doesn't have to be specifically INTRODUCE that triggers UNRECOGNIZED SERVER.