Library and benchmark program for Arctic and Shine

Ian Goldberg 4a5cb38b30 gen now returns (Scalar, RistrettoPoint) to match the paper 3 months ago
src 4a5cb38b30 gen now returns (Scalar, RistrettoPoint) to match the paper 3 months ago
Cargo.toml 55187fb080 Use itertools::combinations instead of rolling our own 3 months ago