Library and benchmark program for Arctic and Shine

Ian Goldberg 4a5cb38b30 gen now returns (Scalar, RistrettoPoint) to match the paper hai 11 meses
src 4a5cb38b30 gen now returns (Scalar, RistrettoPoint) to match the paper hai 10 meses
Cargo.toml 55187fb080 Use itertools::combinations instead of rolling our own hai 10 meses