Improved cutscenes

* Added missing cutscene packet that doesn't seem to do anything.
* Added callback OnFinish
Added client event handling

Client events are triggered by the client, for example when entering a
specific area.
Follow up bf019ad6d0f0846ebc4080c0b04c81d1f3c147d8

* Fixed mistake with the Event/SignalType.
* Added at least a region check for SignalType.Enter.
Added "tuto_meet_tin" cutscene