Potential Upstream library improvements

[ValarDragon]

This issue is meant to keep track of ways the efficiencies of the curve libraries can be sped up.
For Altbn128 (and perhaps BLS12-381, I haven't investigated it for this), lattices of endomorphisms can be used to speed up point scalar multiplication on G1 and G2, as specified in https://link.springer.com/chapter/10.1007%2F3-540-44647-8_11

For both of these, the product of pairings as specified in https://eprint.iacr.org/2006/172.pdf can be implemented to speed up most applications.