add encrypted slack token to travis.yml
use travis.yml indentation that the travis cli created
split weak_* attributes into client and server ones
add tests for new weak_ attribs and transition logic
update docs about split of cbc_required, weak_hmac and weak_kex
Merge pull request #49 from bkw/splitWeakCipers

allow cbc, hmac and kex to be configured individually for client and server.
Merge pull request #51 from bkw/addSlackNotification

Add slack notifications
add deprecation warning when ssh_rootkey(s) used in data bag
update docs about deprecated use of data bag `users`.