Zero point for SWJacobian

[DanieleDiBenedetto]

Hi, shouldn't the zero point in SW Jacobian be any point of the form (t^2:t^3:0) with t <> 0 (conventionally represented with (1:1:0)), instead of (0:1:0), which is actually the zero point in SWProjective ?

bls12_381/src/g1.rs

Line 516 in e32494e

pub fn identity() -> G1Projective {

[ebfull]

Originally the code was using projective formulas, and I actually think I might switch to them (after some benchmarks) but I wanted to have an implementation with Jacobian to benchmark against after other optimizations have been written, that way I know it's worth it. (#2)

The choice of representation here doesn't matter though. The API does not provide access to the raw coordinates, so this can be switched later without breaking anything.