Bump ZAS to v1.15.0
Merge pull request #57 from zendesk/trav/bump_zas

Bump ZAS to v1.15.0
v1.16.0
rollback ZAS
Merge pull request #58 from zendesk/likun/revert_zas_change

rollback ZAS
bump 1.17.0
Merge branch 'master' of github.com:zendesk/zendesk_apps_tools into olaf/yaml_settings