iang/arctic: Library and benchmark program for Arctic and Shine @ 4a5cb38b307dc9eda476f4cfbbbb55ad9a16cb72

Library and benchmark program for Arctic and Shine

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