Simplifies BIP-322 to ONLY address signing/verifying a message, removing traces of proof-of-funds. Also adds some missing fields that were asked for, such as lock time and sequence.
The intention is to make a separate BIP which builds on top of this one for the proof of funds part.
Edit: I am still trying to figure out this and a separate BIP which addresses the proof of funds part. Not ready for merging yet.