PERI-3 expose more RM ports
Merge pull request #273 from sequenceiq/ports

PERI-3 expose more RM ports
CLOUD-61 validate PUT changed to accept decommisions
CLOUD-61 validate stack PUT changed to accept valid negative scaling adjustments
CLOUD-61 'removable' field added to instancemetadata to be able to track which instances can be removed from a stack
CLOUD-61 handle negative scalingAdjustments on stack
CLOUD-61 aws implementation of remove instances
CLOUD-61 handle stack update success
CLOUD-61 decommision cluster hosts
CLOUD-61 decommision success handling
CLOUD-61 call decommision requests asynchronously instead of calling removeHosts directly