* Fix DialogueLine not shown in custom TimelineTrack
* Make example scene.
* Delete not used script: DialogueMixerBehaviour.cs
* Push uncommited changes
* Fix minor bug
while timeline is playing, click on ExampleCutscene object, you get an error. This prevent that error.
* Inverted the checks
In preparation for making the tool work also in Edit mode
Co-authored-by: Ciro Continisio <ciro@unity3d.com>