Various heap-allocated bitset implementations in Rust.
At the moment we provide a `DenseBitSet` datastructure, and plan to provide compressed and memory-mapped
bitsets in the near future.
```rust
use bitsets::DenseBitSet;
let A = DenseBitSet::from_bits(0b1001100000100010);
let B = DenseBitSet::from_bits(0b1001100000100010);
let C = A.or(&B);
```