Support lambda-term 3.3.x

[barracuda156]

@Piervit lambda-term is at 3.3.2 now: https://opam.ocaml.org/packages/lambda-term/lambda-term.3.3.2
Can it be supported? Opam page states < 3.3.0: https://opam.ocaml.org/packages/gufo

[barracuda156]

Upd. Nah, issue #2 is due to camomile.