Schnorr signatures BIP

A proposed BIP for 64-byte elliptic curve Schnorr signatures has been shared by Pieter Wuille via bitcoin-dev. The BIP serves as a draft specification of the signature scheme itself and aims to standardize the signature scheme, which is the first step towards integrating it into Bitcoin. The proposal does not concern consensus rules or aggregation. The encoding of public (and private) keys is unspecified in the BIP, leading to a discrepancy between the specification and the test vectors. As a consequence, even the Python reference implementation in the BIP draft doesn't work on test vectors. The author hopes that more production-ready reference implementations and tests will be developed if the BIP is accepted.