This commit exports several commonly used methods that can be used by later migrations. It also adds a channel commit deserializer.
This commit was previously split into the following parts to ease review: - 2d746f68: replace imports - 4008f0fd: use ecdsa.Signature - 849e33d1: remove btcec.S256() - b8f6ebbd: use v2 library correctly - fa80bca9: bump go modules