Provide 'advance' orange widget designs

TODO

should be merge first:

• ewokscore!21 (merged)

• !9 (merged)

• add documentation

  • general information
  • information regarding the two possible designs (inherit from OWEwoksWidget or Registered)

• add an example and test cases for the Registered use case

  • provide advancement to orange and do processing on a thread

• publish documentation on pages (should be done once merged on master)

• add an BaseOWesrfTask
  • make current OWEwoksWidget
  • one class for each of those use cases:
    • launch a new thread per request
    • single processing thread: refuse request if already processing
    • single thread with a stack
  • see what is the best way to handle progress on those use cases and with Task.
  • split binding into several file