Rewrite some functions in terms of fold
Design ROBDD structure
Redesign
Implement fold
Implement restrict
Implement exists and forall
Strengthen type safety using a phantom type variable
Rename Data.OBDD to Data.OBDD.Reduced and slightly rearrange some code
Rename IdPoolM to ROBDDM
Spell Robdd with all but the first letter in lowercase
Restructure
Use == instead of equals for comparing Robdds
Add constM
Improve encapsulation
Update cabal file