A bitset whose size is fixed at compile-time.
```rust use fixed_bitset::Bitset; use typenum::consts::*;
let mut set = Bitset::
set.insert(20); set.insert(70); // set.insert(100); // WILL PANIC!
let values: Vec
let mut superset = set.clone(); superset.insert(50);
assert!(superset.issuperset(&set)); assert!(set.issubset(&superset));
let difference = &superset - &set;
asserteq!(difference.iter().collect::