fix wrong VoteTopicMessage.asPlainText
adjust VoteTopicMessage json parse order
add test of VoteTopicMessage save and load
use VoteTopicMessage as lock when update results and json serialization
clean import
introduce additionalDigestString to makes digest  string can be different to  asPlainText(for db save)
VoteTopicMessage digestId use plainText header unchanged part as digest string ,avoid simple string-concert different part same concert result digest
VoteOfMe message use additionalDigestString interface
clean import
correct construct complete message
add test of VoteOfMeMessage update VoteTopicMessage