Both ExecBroker and ExecWorker use 'options'

[Zarquan]

Both web services are self-describing, using the options pattern to describe what the client can do.

ExecutionBroker broker response

offers:
- ident: 001
  status: "OFFERED"
  ....
  options:
  - path: "status"
    values: ["ACCEPTED, REJECTED"]
....

ExecutionBroker individual offer

offer:
- ident: 001
  status: "OFFERED"
  ....
  options:
  - path: "status"
    values: ["ACCEPTED, REJECTED"]
....

ExecutionWorker individual session

session:
- ident: 361
  status: "RUNNING"
  ....
  options:
  - path: "status"
    values: ["CANCELLED"]
....