Update: monadisation of Lutin, part 5 + remove support for the fair mode.
Rationale: make rdbg time traveling work. Rationale for removing the fair mode: - the code for choosing the mode was ugly - it duplicates the effort - they other means to be fair (via weigths) - it can be very expensive (it breaks the sharing in the bdd, and computing polyedron volume is costly). hence it is not in the spirit of all the tradeoffs used elsewhere in design choices. - I've never used it (well, except in the tuto...)