New feature: revoke an unwanted identity

Some of you asked me several times to delete an identity they submitted to a node, making it appear under /wot/lookup, but wanting to remove it for some reason (it was a mistake, had a wrong character, etc).

You are now able to do this by yourself using last version of ucoin-cli (aka. vucoin).

Usage is:

$ ucoin --salt <salt> --passwd <password> --host --port 9101 --send revoke <uid>

For example, to remove UID “mybaduid”, simply run:

$ ucoin --salt <salt> --passwd <password> --host --port 9101 --send revoke mybaduid

N.B.: this command will never remove an identity already written in the blockchain.