• Add new OpenStack Keystone authentication backend.
  [Itxaka Serrano]
• Information about parent workflow is now a dict in child's context field. (improvement)
• Fix a bug when some runner parameter default values where not overridden when a
  falsey value was used in the action metadata parameter override (e.g. False, 0).
  [Eugen C.]
• Correctly return 404 if user requests an invalid path which partially maps to an existing
  path. (bug-fix)
• Add support for restarting sensors which exit with a non-zero status code to
  the sensor container. Sensor container will now automatically try to restart
  (up to 2 times) sensor processes which die with a non-zero status code. (improvement)
• Support for RabbitMQ cluster. StackStorm works with a RabbitMQ cluster and switches
  nodes on failover. (feature)
• Add index to the ActionExecution model to speed up query. (improvement)
• Fix sort key in the ActionExecution API controller. (bug-fix)
• Introduce a Paramiko SSH runner that uses eventlets to run scripts or commands in parallel. (improvement) (experimental)
• Add action parameters validation to Mistral workflow on invocation. (improvement)
• Fix key name for error message in liveaction result. (bug-fix)
• Fix 500 API response when rule with no pack info is supplied. (bug-fix)
• Fix bug in trigger-instance re-emit (extra kwargs passed to manager is now handled). (bug-fix)
• Rename notification "channels" to "routes". (improvement)
• Make sure auth hook and middleware returns JSON and "Content-Type: application/json" header
  in every response. (improvement, bug-fix)
• Fix bug in triggers emitted on key value pair changes and sensor spawn/exit. When
  dispatching those triggers, the reference used didn't contain the pack names
  which meant it was invalid and lookups in the rules engine would fail. (bug-fix)
• Allow user to include files which are written on disk inside the action create API payload.
  (new feature)
• Allow user to retrieve content of a file inside a pack by using the new
  /packs/views/files/ API endpoint. (new feature)
• Handle sudo in paramiko remote script runner. (bug-fix)
• Turn on paramiko ssh runner as the default ssh runner in prod configuration.
  To switch to fabric runner, set use_paramiko_ssh_runner to false in st2.conf. (improvement)
• Add OpenStack Keystone authentication configuration for Mistral. (improvement)
• Abiltiy to add trace tag to TriggerInstance from Sensor. (feature)
• Ability to view trace in CLI with list and get commands. (feature)
• Add ability to add trace tag to st2 run CLI command. (feature)
• Add ability to specify trace id in st2 run CLI command. (feature)
• Update st2ctl to correctly start st2web even if even if Mistral is no installed.
  (bug-fix, improvement)
• Add X-Request-ID header to all API calls for easier debugging. (improvement)
• Add new CLI commands for disabling and enabling content pack resources
  ({sensor,action,rule} {enable, disable} <ref or id>) (feature)
• Fix a bug in handling positional arguments with spaces. (bug-fix)
• Make sure that the $PATH environment variable which is set for the sandboxed Python
  process contains "/bin" directory as the first entry. (bug fix)