Overload API with Simple Generator Alternatives

[SSoelvsten]

As a follow-up on #532 (similar to the aliases in #452), we should provide the following overloads

• [x] bdd_restrict(bdd f, bdd::label_type x, bool v) ( done for #557 )
• [ ] bdd_restrict(bdd f, int x)
• [ ] zdd_change(const zdd&, zdd::label_type var)
  • [ ] Additionally, add the ^ and ^= operator overloads where the second argument is a zdd::label_type.
• [ ] zdd_expand(const zdd&, zdd::label_type var)

And of course, this should be unit tested.