Macro multi_pairing

macro_rules! multi_pairing {
    ($($g1: expr, $g2: expr);+) => { ... };
    (using $pairing_engine: path: $($g1: expr, $g2: expr);+) => { ... };
}

Calculates the product of pairing for supplied pairs.

multi_pairing! {
    a, c,
    b, d
}

Will be transformed to:

E::multi_pairing([a, b], [c, d])