* Ed25519 async batch verification for JoinSplit signatures
We've been verifying JoinSplitSigs one-by-one pre-ZIP-215. Now as we're post-ZIP-215,
we can take advantage of the batch math to validate this signatures.
I would have pumped all the joinsplits in our MAINNET_BLOCKS test vectors but these
signatures are over the sighash, which needs the NU code to compute, and once we're
doing all that set up, we're basically doing transaction validation, so.
Resolves#1944
* Repoint to latest ed25519-zebra commit with note to point at 3.0 when released
Co-authored-by: Alfredo Garcia <oxarbitrage@gmail.com>
Co-authored-by: teor <teor@riseup.net>