Fix base58check-decode to conform to sx
Commands using interactArgs can now be used without arguments (same as a single `-`)
[refactor] rename checksum_{en,de}code to chksum32_{en,de}code
[refactor] hx brainwallet
Add support for chksum32-{encode,decode}
Commands btc and satoshi can now read from stdin.
Re-org the help message / README
The argument of validaddr can now be omitted and read from stdin