`bdd_varnum` is a too general name, as it only refers to BDD variables

[magoorden]

From #31.

The below code uses cdd_varnum and here we have cdd_clocknum -- are these the same?

cdd_varnum is the "number of BDD variables" and cdd_clocknum the "number of clocks" (see kernel.h). So they are different. I agree that cdd_varnum is a little bit misleading, as both boolean variables and clocks can be though of as variables. I will create an issue for this to change the naming separately.