- added callbacks parameters to hbugsClient constructor (on_exit,

- added callbacks parameters to hbugsClient constructor (on_exit,
  on_use_hint)
- hid methods used to handle local http daemon
- added and exposed methods registerToBroker, unregisterFromBroker,
  subscribeAll
- removed useHint, hint are returned on request by "hint" new method
- remeber availableTutors from last List_tutor message and use them to
  show tutors name instead of tutor id in main window
- handle double click on hint name to use an hint
- added wait parameter sendReq method to be able to wait the answer of
  a request
- added support for multiple hints received from broker
- clear old hints on state change
- subscribe to all available tutors on creation
- added subscribeSelected method