updade MessageArchive to do timebased keys
Merge branch 'master' of github.com:rit-sse-mycroft/core
Merge branch 'master' of github.com:rit-sse-mycroft/core
Merge branch 'master' of github.com:rit-sse-mycroft/core
add MessageArchive and tests for it
Merge branch 'master' of github.com:rit-sse-mycroft/core