exit added to multi/singlenode blueprint
debug goest to stderr so it can be filtered out
serf tag made orthogonal: --tags ambari-server=true --tag ambari-agent=true (DRY_RUN capability)

old hack was:
  --tag ambari-role=server,agent
but a tag shouldn't contain a coma separated list ...
i mean tags are for this very reason: give multiple tags
naive integration test for event-handler shell script, consider: https://github.com/sstephenson/bats
ambari-shell scripts are moved to https://github.com/sequenceiq/docker-ambari-shell
fix quotation bug in command execution
fit serf tag: ambari-server=true I'm ambari-functions