v0.9.0

This release brings reliability improvements, as well as a task cleanup operation (coconut task clean).

• Task cleanup:
  • [coconut] Implement task clean operation and improve error handling
  • [core] Send task kill call from scheduler
  • [core] Implement server side of tasks cleanup API call
  • [core] task.Task now has a state/status
  • [core] Allow sending control commands to non-locked tasks
  • [core] Implement task cleanup in task.Manager
  • [core] Update environment transitions for new interface in task.Manager
  • [executor] Allow executor to create its own executorcommands
  • [executor] Fix bug with bad final state in FairMQ transitioner
  • [executor] Implement KILL event + improve error handling