SKA Base Class Master - abort command execution

Execution of the commands On(), Off() and Standby() can be aborted, i.e. command execution stopped, the subordinate components/devices remain in the current state. Abort may be forwarded to the subordinate components where the command was forwarded and execution is in progress (details of implementation must be considered for each command and component), but there is no guarantee regarding the result (i.e. if the transition to Off() was already performed but not reported or cannot be stopped). In any case all the subordinate components and the Master must at any time to report status.

At all stages during execution of the command Abort(), the ObsDevice derives the overall operational state, health and other attributes and reports as needed (via events or poling).

Detailed design in progress.