sidestr-core 0.2.1

sidestr user-activated sidechains beside a Bitcoin-family parent: the chain document, the parents table, signed blocks generic over the header family (BIP-325 challenge, no subsidy), the peg-in claim and peg-out burn rules, Knots' unified sighash, the block file and an in-memory validating chain. A port of siding by Melvin Carvalho.