CLOUD-290 do not allow to decommission any host group which contains a MASTER service
CLOUD-290 error handling for bad requests when decommission
CLOUD-290 service component check moved to upper to give proper information to the user
CLOUD-290 do not allow multiple scaling group in one request
CLOUD-309 configurable reactor thread pool size with default value
Merge pull request #359 from sequenceiq/decomm

Do not decommission host groups with MASTER components
Merge pull request #361 from sequenceiq/reac

CLOUD-309 configurable reactor thread pool size with default value
CLOUD-319 use the custom user pass when restarting cluster
Merge pull request #362 from sequenceiq/pass

CLOUD-319 use the custom user pass when restarting cluster
CLOUD-400 subscribe endpoint for clients
CLOUD-267 check if the requested subscription already exist
CLOUD-267 dummy notification sending mechanism
CLOUD-267 create notification for start/stop and set ambari ip as AVAILABLE event message
CLOUD-267 create notification from cloudbreakevents
CLOUD-267 create cluster creation failed event
CLOUD-282 add CloudbreakEvent new fields to Notification
CLOUD-267 validate url field in SubscribeRequest
CLOUD-273 uptime is counted from last start time
CLOUD-267 update log of event creation
CLOUD-267 add proper cause to stack status updates