use isHash, not isBuffer
put the chosen hash in the message
tag the hash with the current algorithm
allow previous on init to be nullish
tidy
note about createFeedStream
use explain-error to make test/validation easier to debug
support string hashes in test/defaults
use explain-error
use new style of messages
client has been moved into scuttlebot
update tests to use base64 strings instead of buffers
remove deps that are no longer needed
drop json-buffer
remove msgpack-js and continuable-para
tidy
keys and signatures as tagged base64
refactor out crytpo into ssb-keys
codec is separate to crytpo
6.0.0